SELECT 
  * 
FROM 
  cscart_product_options_inventory 
WHERE 
  product_id = 9931 
  AND combination_hash = '2985498231'

Query time 0.00030

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
9931 ODF-AFZBAAA05101 2985498231 595_15410_596_14859 0.00 N 0 1200.00 2.03 0 0 0 0 123