SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e4c9a717f3ec4227b800ee606782de329f7434e98ecf12b894bb9e905a96602' 
  AND token = 'JOGHx+VhMFJjKI6Kl5yHJDIpKWoMGZQh6LUpS95KiS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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