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SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description, 
  cscart_product_descriptions.meta_keywords, 
  cscart_product_descriptions.meta_description, 
  cscart_product_descriptions.search_words, 
  cscart_product_descriptions.promo_text 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (98567, 97531, 98882) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00037

Explain
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	cscart_product_descriptions	range	PRIMARY,product_id	PRIMARY	9		3	Using where

Result

product_id	short_description	full_description	meta_keywords	meta_description	search_words	promo_text
97531					INFEXORI004,InfeXious Origins,2 Brothers Of Hardstyle,Jimmy The Sound,Delfromad,Clive King
98567					KTRAR046,Keeping The Rave Alive,David Rust
98882					INFEXORI006,InfeXious Origins,Clive King,B-Savage