SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33f8d62d638c050672e7600ef6f4b7c4302f989523448c35a72075231d7d800d' 
  AND token = 'xKyFKm6u8wBj+PpjAckzHHgYtg6e1+h8djM4gqP4lZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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