You cannot use the most common wireless system, Bluetooth, because that has significant latency.
But there are some proprietary wireless systems that have no significant latency, because wireless mics and other instruments use them. The Boss WL system for example. Most of these systems are designed for guitar and bass players, but don’t see why it would not work for a keyboard. I am not sure how good the quality would be, but it might work quite well. I think the best way forward would be to talk with someone at a really good music/audio store and get advice.
Mike