SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a9b5c8015de0675a993151693f23560aeb54541013f50e23ccf474c6d09131df' 
  AND token = 'CzAr7uGipqgBGPicChDOzyDRUDZtIORxnasbkVjsh9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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