SELECT 
  cscart_profile_fields.*, 
  cscart_profile_field_descriptions.description, 
  cscart_profile_fields.checkout_required as required 
FROM 
  cscart_profile_fields 
  LEFT JOIN cscart_profile_field_descriptions ON cscart_profile_field_descriptions.object_id = cscart_profile_fields.field_id 
  AND cscart_profile_field_descriptions.object_type = 'F' 
  AND lang_code = 'vi' 
WHERE 
  1 = 1 
  AND cscart_profile_fields.profile_type = 'U' 
  AND cscart_profile_fields.section = 'S' 
  AND cscart_profile_fields.checkout_show = 'Y' 
ORDER BY 
  cscart_profile_fields.position

Query time 0.00131

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "read_sorted_file": {
          "filesort": {
            "sort_key": "cscart_profile_fields.position",
            "table": {
              "table_name": "cscart_profile_fields",
              "access_type": "ALL",
              "possible_keys": ["checkout_show"],
              "rows": 45,
              "filtered": 42.22222137,
              "attached_condition": "cscart_profile_fields.profile_type = 'U' and cscart_profile_fields.section = 'S' and cscart_profile_fields.checkout_show = 'Y'"
            }
          }
        }
      },
      {
        "table": {
          "table_name": "cscart_profile_field_descriptions",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "12",
          "used_key_parts": ["object_id", "object_type", "lang_code"],
          "ref": ["dev_db.cscart_profile_fields.field_id", "const", "const"],
          "rows": 1,
          "filtered": 100,
          "attached_condition": "trigcond(cscart_profile_field_descriptions.object_type = 'F' and cscart_profile_field_descriptions.lang_code = 'vi')"
        }
      }
    ]
  }
}