SELECT 
  object_id 
FROM 
  cscart_seo_names 
WHERE 
  type = 'a' 
  AND name IN (
    '모터스베이-이용약관', 
    'motorsbay-terms-of-service'
  ) 
ORDER BY 
  FIELD(lang_code, 'ru', 'ko', 'en') 
LIMIT 
  1

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "read_sorted_file": {
      "filesort": {
        "sort_key": "field(cscart_seo_names.lang_code,'ru','ko','en')",
        "table": {
          "table_name": "cscart_seo_names",
          "access_type": "range",
          "possible_keys": ["name", "type"],
          "key": "name",
          "key_length": "752",
          "used_key_parts": ["name"],
          "rows": 5,
          "filtered": 100,
          "index_condition": "cscart_seo_names.`name` in ('모터스베이-이용약관','motorsbay-terms-of-service')",
          "attached_condition": "cscart_seo_names.`type` = 'a'"
        }
      }
    }
  }
}