SELECT 
  id_path 
FROM 
  cscart_categories 
WHERE 
  category_id IN (197, 198, 199)

Query time 0.00028

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE cscart_categories range PRIMARY,p_category_id PRIMARY 3 3 Using index condition

Result

id_path
166/196/197
166/196/198
166/196/199