SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    397, 879, 839, 259, 387, 389, 388, 404, 
    396, 872, 373, 856, 833, 878
  )

Query time 0.00037

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

Result

category_id parent_id
387 259
389 259
388 259
404 259
872 259
373 259
856 259
397 396
846 833
839 833
879 878