SELECT 
  service_id 
FROM 
  cscart_shipping_services 
WHERE 
  module = 'ghn' 
  AND code = 'delivery_basic'

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "27.07"
    },
    "table": {
      "table_name": "cscart_shipping_services",
      "access_type": "ALL",
      "rows_examined_per_scan": 260,
      "rows_produced_per_join": 2,
      "filtered": "1.00",
      "cost_info": {
        "read_cost": "26.81",
        "eval_cost": "0.26",
        "prefix_cost": "27.07",
        "data_read_per_join": "1K"
      },
      "used_columns": [
        "service_id",
        "module",
        "code"
      ],
      "attached_condition": "((`kcoffee`.`cscart_shipping_services`.`module` = 'ghn') and (`kcoffee`.`cscart_shipping_services`.`code` = 'delivery_basic'))"
    }
  }
}