SELECT 
  * 
FROM 
  cscart_product_options_inventory 
WHERE 
  product_id = 3320 
  AND combination_hash = '2192438395'

Query time 0.00025

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
3320 ATR-OID426I0509 2192438395 971_19299 15.00 N 0 226.80 2.00 0 0 0 0 1