SELECT 
  * 
FROM 
  cscart_product_options_inventory 
WHERE 
  product_id = 10350 
  AND combination_hash = '2168542392'

Query time 0.00022

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
10350 EPS-PAR-PLP-020 2168542392 765_16401 0.00 N 0 9.72 5.00 1 0 15 0 0