SELECT 
  * 
FROM 
  cscart_product_options_inventory 
WHERE 
  product_id = 438 
  AND combination_hash = '1128304682'

Query time 0.00021

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
438 RCK-FAS-281752 1128304682 336_7668 0.00 N 50 42.83 24000.00 1 0 57.6 0 100