SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    915, 435, 881, 888, 450, 460, 467, 471
  )

Query time 0.00026

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE cscart_categories range parent parent 3 8 Using index condition