SELECT 
  processor_id 
FROM 
  cscart_payment_processors 
WHERE 
  processor_script = 'vnpay_qr.php'

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "7.87"
    },
    "table": {
      "table_name": "cscart_payment_processors",
      "access_type": "ALL",
      "rows_examined_per_scan": 69,
      "rows_produced_per_join": 6,
      "filtered": "10.00",
      "cost_info": {
        "read_cost": "7.18",
        "eval_cost": "0.69",
        "prefix_cost": "7.87",
        "data_read_per_join": "21K"
      },
      "used_columns": [
        "processor_id",
        "processor_script"
      ],
      "attached_condition": "(`kcoffee`.`cscart_payment_processors`.`processor_script` = 'vnpay_qr.php')"
    }
  }
}