SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fa6a097f86cea395971b2faec5f3546df891d81433a77403b2b168e60daeeeef' 
  AND token = 'PONqmxBd2EpmjEZOxB7Js4FrZ40wrIauWBW2hiKJCvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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