SELECT 
  * 
FROM 
  cscart_product_options_inventory 
WHERE 
  product_id = 2142 
  AND combination_hash = '1852799938'

Query time 0.00073

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
2142 ODF-839901 1852799938 535_14038 0.00 N 0 180.00 0.56 0 0 0 0 5