SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd33c35e03535257609a3cf16ed8df77732fea1f65175cf42625c0fc336a2296' 
  AND token = 'RpkG4J+7bXZ6b0ZDyKvprufvRsWNh8RjcDnX/jt4wms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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