SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '395bca2420ea0dc7493a01a827f73521b4f4d06ea1da3eef23d16ca65452eee5' 
  AND token = 'DysjyZYkXtISyJcAzCwRycz9+zsOyPzrG5VgAZB38i4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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