Sandbox

SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    869, 761, 782, 868, 796, 806, 918, 811, 
    816, 823
  )

Explain
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	cscart_categories	range	parent	parent	3		21	Using index condition