Sandbox

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 (
    767, 769, 1561, 783, 782, 1564, 786, 787, 
    2870, 789, 790, 792, 2887, 793, 807, 
    808, 810, 811, 2216, 813
  ) 
  AND cscart_ult_product_descriptions.company_id = 1 
  AND cscart_ult_product_descriptions.lang_code = 'ru'

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "Impossible WHERE noticed after reading const tables"
  }
}