I am new to FLutter and learning it to my own. I want to get the object key using the query from Firebase Realtime Database as highlighted in below screen shot:

My Query Method is:
void queryDB(BuildContext context) async {
AppUtil.showLoader(context: context);
String userId = "u1";
FirebaseDatabase.instance.ref('usersnode/users').orderByChild('userId').equalTo("u1").get().then((snapshot) {
if (snapshot.exists) {
print("KEY:::" + snapshot.key);
} else {
print('No data available.1');
}
AppUtil.dismissLoader(context: context);
});
}
It always print users but my expectation is to get 0
Thanks in Advance