SELECT 
  a.category_id 
FROM 
  cscart_categories as a 
  LEFT JOIN cscart_categories as b ON b.category_id IN (562) 
WHERE 
  a.id_path LIKE CONCAT(b.id_path, '/%')

Query time 0.00041

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE b const PRIMARY,p_category_id PRIMARY 3 const 1
1 SIMPLE a ALL 214 Using where

Result

category_id
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720