SELECT 
  product_id 
FROM 
  cscart_ec_extra_product_data 
WHERE 
  company_id = 6

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "6.83"
    },
    "table": {
      "table_name": "cscart_ec_extra_product_data",
      "access_type": "ALL",
      "rows_examined_per_scan": 23,
      "rows_produced_per_join": 2,
      "filtered": "10.00",
      "cost_info": {
        "read_cost": "6.37",
        "eval_cost": "0.46",
        "prefix_cost": "6.83",
        "data_read_per_join": "110"
      },
      "used_columns": [
        "product_id",
        "company_id"
      ],
      "attached_condition": "(`atulecarter_atul_demo1`.`cscart_ec_extra_product_data`.`company_id` = 6)"
    }
  }
}