SELECT 
  COUNT(DISTINCT products.product_id) 
FROM 
  cscart_products as products USE INDEX (idx_products_composite_query) 
  INNER JOIN cscart_product_features_values as c_var ON c_var.product_id = products.product_id 
  AND c_var.lang_code = 'en' 
  AND c_var.variant_id = 25037 
  LEFT JOIN cscart_companies AS companies ON companies.company_id = products.company_id 
  INNER JOIN cscart_products_categories as products_categories USE INDEX (
    idx_products_categories_composite
  ) ON products_categories.product_id = products.product_id 
  INNER JOIN cscart_categories ON cscart_categories.category_id = products_categories.category_id 
  AND cscart_categories.status IN ('A', 'H') 
  AND cscart_categories.storefront_id IN (0, 1) 
  LEFT JOIN cscart_product_sales USE INDEX (
    idx_product_sales_category_amount
  ) ON cscart_product_sales.product_id = products.product_id 
  AND cscart_product_sales.category_id = products_categories.category_id 
WHERE 
  1 
  AND (
    companies.status IN ('A') 
    OR products.company_id = 0
  ) 
  AND products.company_id IN (13, 0) 
  AND (
    products.amount > 0 
    OR products.tracking = 'D'
  ) 
  AND products.status IN ('A') 
  AND products.parent_product_id = 0 
  AND products.master_product_status IN ('A') 
  AND products.master_product_id = 0 
  AND products.company_id > 0

Query time 0.05654

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "18773.80"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "products",
          "access_type": "range",
          "possible_keys": [
            "idx_products_composite_query"
          ],
          "key": "idx_products_composite_query",
          "used_key_parts": [
            "status",
            "company_id",
            "master_product_status",
            "master_product_id",
            "parent_product_id"
          ],
          "key_length": "18",
          "rows_examined_per_scan": 15774,
          "rows_produced_per_join": 6309,
          "filtered": "40.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "2568.71",
            "eval_cost": "630.91",
            "prefix_cost": "3199.62",
            "data_read_per_join": "32M"
          },
          "used_columns": [
            "product_id",
            "status",
            "company_id",
            "amount",
            "tracking",
            "parent_product_id",
            "master_product_id",
            "master_product_status"
          ],
          "attached_condition": "((`cscart_db`.`products`.`master_product_id` = 0) and (`cscart_db`.`products`.`parent_product_id` = 0) and (`cscart_db`.`products`.`company_id` in (13,0)) and ((`cscart_db`.`products`.`amount` > 0) or (`cscart_db`.`products`.`tracking` = 'D')) and (`cscart_db`.`products`.`status` = 'A') and (`cscart_db`.`products`.`master_product_status` = 'A') and (`cscart_db`.`products`.`company_id` > 0))"
        }
      },
      {
        "table": {
          "table_name": "c_var",
          "access_type": "ref",
          "possible_keys": [
            "variant_id",
            "lang_code",
            "product_id",
            "idx_product_feature_variant_id"
          ],
          "key": "idx_product_feature_variant_id",
          "used_key_parts": [
            "product_id"
          ],
          "key_length": "3",
          "ref": [
            "cscart_db.products.product_id"
          ],
          "rows_examined_per_scan": 17,
          "rows_produced_per_join": 315,
          "filtered": "0.29",
          "using_index": true,
          "cost_info": {
            "read_cost": "4061.70",
            "eval_cost": "31.55",
            "prefix_cost": "18259.45",
            "data_read_per_join": "12K"
          },
          "used_columns": [
            "product_id",
            "variant_id",
            "lang_code"
          ],
          "attached_condition": "((`cscart_db`.`c_var`.`variant_id` = 25037) and (`cscart_db`.`c_var`.`lang_code` = 'en'))"
        }
      },
      {
        "table": {
          "table_name": "companies",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "company_id"
          ],
          "key_length": "4",
          "ref": [
            "cscart_db.products.company_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 315,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "78.86",
            "eval_cost": "31.55",
            "prefix_cost": "18369.86",
            "data_read_per_join": "2M"
          },
          "used_columns": [
            "company_id",
            "status"
          ],
          "attached_condition": "<if>(found_match(companies), ((`cscart_db`.`companies`.`status` = 'A') or (`cscart_db`.`products`.`company_id` = 0)), true)"
        }
      },
      {
        "table": {
          "table_name": "products_categories",
          "access_type": "ref",
          "possible_keys": [
            "idx_products_categories_composite"
          ],
          "key": "idx_products_categories_composite",
          "used_key_parts": [
            "product_id"
          ],
          "key_length": "3",
          "ref": [
            "cscart_db.products.product_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 364,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "135.48",
            "eval_cost": "36.43",
            "prefix_cost": "18541.77",
            "data_read_per_join": "5K"
          },
          "used_columns": [
            "product_id",
            "category_id"
          ]
        }
      },
      {
        "table": {
          "table_name": "cscart_categories",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY",
            "p_category_id",
            "idx_categories_storefront_status",
            "idx_categories_usergroup_status",
            "idx_categories_status_id_path"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "category_id"
          ],
          "key_length": "3",
          "ref": [
            "cscart_db.products_categories.category_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 298,
          "filtered": "81.96",
          "cost_info": {
            "read_cost": "91.08",
            "eval_cost": "29.86",
            "prefix_cost": "18669.29",
            "data_read_per_join": "835K"
          },
          "used_columns": [
            "category_id",
            "status",
            "storefront_id"
          ],
          "attached_condition": "((`cscart_db`.`cscart_categories`.`status` in ('A','H')) and (`cscart_db`.`cscart_categories`.`storefront_id` in (0,1)))"
        }
      },
      {
        "table": {
          "table_name": "cscart_product_sales",
          "access_type": "ref",
          "possible_keys": [
            "idx_product_sales_category_amount"
          ],
          "key": "idx_product_sales_category_amount",
          "used_key_parts": [
            "category_id",
            "product_id"
          ],
          "key_length": "6",
          "ref": [
            "cscart_db.products_categories.category_id",
            "cscart_db.products.product_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 298,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "74.65",
            "eval_cost": "29.86",
            "prefix_cost": "18773.80",
            "data_read_per_join": "4K"
          },
          "used_columns": [
            "category_id",
            "product_id"
          ]
        }
      }
    ]
  }
}