SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4c4388af3c2b56c000ab06f2dfdb3df299826d7aa9511265999426122870bd0' 
  AND token = 'IEdOAznXITx9sWYpee56HNdO3imRnF5GNdkSYJHVdTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}