SELECT 
  COUNT(*) 
FROM 
  `cscart_products_categories` 
  JOIN cscart_categories ON (
    cscart_categories.category_id = cscart_products_categories.category_id
  ) 
WHERE 
  cscart_products_categories.`category_id` = 2695 
  AND cscart_categories.status = 'A'

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "42.01"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_categories",
          "access_type": "const",
          "possible_keys": [
            "PRIMARY",
            "p_category_id"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "category_id"
          ],
          "key_length": "3",
          "ref": [
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.00",
            "eval_cost": "0.10",
            "prefix_cost": "0.00",
            "data_read_per_join": "2K"
          },
          "used_columns": [
            "category_id",
            "status"
          ]
        }
      },
      {
        "table": {
          "table_name": "cscart_products_categories",
          "access_type": "ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "category_id"
          ],
          "key_length": "3",
          "ref": [
            "const"
          ],
          "rows_examined_per_scan": 410,
          "rows_produced_per_join": 410,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "1.01",
            "eval_cost": "41.00",
            "prefix_cost": "42.01",
            "data_read_per_join": "6K"
          },
          "used_columns": [
            "category_id"
          ]
        }
      }
    ]
  }
}