Sandbox

SELECT 
  category_id, 
  category 
FROM 
  cscart_category_descriptions 
WHERE 
  category_id IN (261, 901, 359) 
  AND lang_code = 'en'

Explain
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	cscart_category_descriptions	range	PRIMARY	PRIMARY	9		3	Using index condition