SELECT 
  cscart_product_feature_variants.variant_id, 
  cscart_product_feature_variants.position, 
  cscart_product_feature_variants.color, 
  cscart_product_feature_variant_descriptions.variant, 
  cscart_product_feature_variant_descriptions.brand_logo 
FROM 
  cscart_product_feature_variants 
  LEFT JOIN cscart_product_feature_variant_descriptions ON cscart_product_feature_variants.variant_id = cscart_product_feature_variant_descriptions.variant_id 
  AND cscart_product_feature_variant_descriptions.lang_code = 'en' 
WHERE 
  cscart_product_feature_variants.variant_id IN (
    21577, 21578, 21579, 21580, 21581, 21583, 
    21584, 35798, 20886, 27572, 0, 20846, 
    20913, 20932
  ) 
ORDER BY 
  cscart_product_feature_variants.position ASC, 
  cscart_product_feature_variant_descriptions.variant ASC

Query time 0.00056

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "14.71"
    },
    "ordering_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_product_feature_variants",
            "access_type": "range",
            "possible_keys": [
              "PRIMARY",
              "variant_feature_idx",
              "idx_var_feat_pos"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "variant_id"
            ],
            "key_length": "3",
            "rows_examined_per_scan": 14,
            "rows_produced_per_join": 14,
            "filtered": "100.00",
            "index_condition": "(`cscart_db`.`cscart_product_feature_variants`.`variant_id` in (21577,21578,21579,21580,21581,21583,21584,35798,20886,27572,0,20846,20913,20932))",
            "cost_info": {
              "read_cost": "8.41",
              "eval_cost": "1.40",
              "prefix_cost": "9.81",
              "data_read_per_join": "15K"
            },
            "used_columns": [
              "variant_id",
              "color",
              "position"
            ]
          }
        },
        {
          "table": {
            "table_name": "cscart_product_feature_variant_descriptions",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "variant_id",
              "lang_code"
            ],
            "key_length": "9",
            "ref": [
              "cscart_db.cscart_product_feature_variants.variant_id",
              "const"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 14,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "3.50",
              "eval_cost": "1.40",
              "prefix_cost": "14.71",
              "data_read_per_join": "104K"
            },
            "used_columns": [
              "variant_id",
              "variant",
              "lang_code",
              "brand_logo"
            ]
          }
        }
      ]
    }
  }
}