You're referring to a thing that you claim doesn't exist. That's interesting.
Do we have proof for existence or existence? We could have an experiment where we attempt to measure the existence at that future time.
I'm worried that leads to a train of thought claiming that the future doesn't exist.
That future time only exists in your mind as a concept. Think about it. It's self-evident for all practical purposes.
Whether the future does exist now in some physical sense is completely irrelevant as long you can't prove/use that for something real.
Your experiment would only prove that there is a now in which the previously described future has become present or not. It's pointless.
Can you define a "single moment" then?
I think it's quite possible to make use of the present. I am doing it now as I am typing this message.