SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3c6bfac21f6c38f4b69818cc7a71da0abf55d0c3137b70d6d525dec8048f39bd' 
  AND token = 'Xn4W5T1fbrv+Lz2ZhHhCgdjLhnJ+qlrya+R8WPuGGCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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