SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '91ed9b05cd87a1c779e111a621b6a606e008fd7a0d0366c3cac2076548236b72' 
  AND token = '8EwHD8sZGbYI6DPDHvavPWXE52xzhf5WMIwEjVJdt6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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