SELECT 
  cscart_ult_product_descriptions.product_id, 
  cscart_ult_product_descriptions.short_description, 
  IF(
    cscart_ult_product_descriptions.short_description = "", 
    cscart_ult_product_descriptions.full_description, 
    ""
  ) AS full_description, 
  cscart_ult_product_descriptions.meta_keywords, 
  cscart_ult_product_descriptions.meta_description, 
  cscart_ult_product_descriptions.search_words, 
  cscart_ult_product_descriptions.promo_text 
FROM 
  cscart_ult_product_descriptions 
WHERE 
  cscart_ult_product_descriptions.product_id IN (
    808, 1274, 1030, 1437, 1780, 1031, 807, 
    1487, 806, 1033, 505, 395
  ) 
  AND cscart_ult_product_descriptions.company_id = 1 
  AND cscart_ult_product_descriptions.lang_code = 'ja'

Query time 0.00089

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_ult_product_descriptions",
      "access_type": "range",
      "possible_keys": ["PRIMARY", "product_id", "company_id"],
      "key": "PRIMARY",
      "key_length": "13",
      "used_key_parts": ["product_id", "lang_code", "company_id"],
      "rows": 12,
      "filtered": 100,
      "index_condition": "cscart_ult_product_descriptions.company_id = 1 and cscart_ult_product_descriptions.product_id in (808,1274,1030,1437,1780,1031,807,1487,806,1033,505,395) and cscart_ult_product_descriptions.lang_code = 'ja'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text
395
505
806
807
808
1030
1031
1033
1274
1437
1487
1780