SELECT 
  block_id, 
  link_text, 
  tooltip 
FROM 
  cscart_abt__ut2_block_descriptions 
WHERE 
  block_id IN (206, 260, 269, 270, 278, 271, 272) 
  AND lang_code = 'vn'

Query time 0.00048

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "3.16"
    },
    "table": {
      "table_name": "cscart_abt__ut2_block_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "block_id",
        "lang_code"
      ],
      "key_length": "10",
      "rows_examined_per_scan": 7,
      "rows_produced_per_join": 7,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "2.46",
        "eval_cost": "0.70",
        "prefix_cost": "3.16",
        "data_read_per_join": "5K"
      },
      "used_columns": [
        "block_id",
        "lang_code",
        "link_text",
        "tooltip"
      ],
      "attached_condition": "((`kcoffee`.`cscart_abt__ut2_block_descriptions`.`block_id` in (206,260,269,270,278,271,272)) and (`kcoffee`.`cscart_abt__ut2_block_descriptions`.`lang_code` = 'vn'))"
    }
  }
}