SELECT 
  * 
FROM 
  cscart_product_options_inventory 
WHERE 
  product_id = 426 
  AND combination_hash = '3461101140'

Query time 0.00020

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
426 SKY-OSB-0507-S SKY-KOF-0507-S 3461101140 1365_24304_614_15104_696_15775 12.00 N 1 1470.00 47.00 0 0 0 0 1