SELECT 
  * 
FROM 
  cscart_product_options_exceptions 
WHERE 
  product_id = 638 
ORDER BY 
  exception_id

Query time 0.00026

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE cscart_product_options_exceptions ref product product 3 const 3 Using where; Using filesort

Result

exception_id product_id combination
1148 638 a:2:{i:660;i:-1;i:178;s:4:"4245";}
1710 638 a:2:{i:660;s:5:"15518";i:178;s:2:"-1";}
1711 638 a:2:{i:660;s:5:"15518";i:178;s:2:"-2";}