SELECT 
  * 
FROM 
  cscart_product_options_inventory 
WHERE 
  product_id = 9938 
  AND combination_hash = '1395405976'

Query time 0.00029

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE cscart_product_options_inventory const PRIMARY,pc PRIMARY 4 const 1

Result

product_id product_code combination_hash combination amount temp position price weight min_qty max_qty qty_step list_qty_count aval_status
9938 KRM-MIZ160714 1395405976 699_15793 648.00 N 1 70.55 2.00 0 0 0 0 1