Some of that depends on the features of your TV...
You might export the slides as a series of discrete images on a flash drive, and the TV might be able to cycle through them. You might not have control of the order of flow, though.
You could export the presentation as a video, and the TV should be able to play the video. Whether it will auto-loop and play continuously, vs. once through is up to the TV.
If you can screen case from an iPhone, iPad or Mac, that gives you the most flexibility - you can play the presentation directly within Keynote, with the auto-advance, and auto-loop settings enabled, and it will play continuously. Doing this wirelessly requires that the TV supports AirPlay.
So.. lots of options. The right one depends on details that you'll need to determine in advance.