SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f08b1f14245100ca60a88c19ec18ab47f2799928ca12e5639deb8a10aee7217f' 
  AND token = 'DMXYYt0GU0vuO+eVZx0VAPqSoWP+BIB5oA4rsVdNIlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}