SELECT 
  * 
FROM 
  cscart_product_options_inventory 
WHERE 
  product_id = 10101 
  AND combination_hash = '3031606860'

Query time 0.00024

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
10101 ODV-KMG-100K 3031606860 643_15365_644_15367 5.00 N 6 1099.19 2.00 0 0 0 0 119