There are several ways to do that very easily. I would suggest either using a shape layer made up of a circle path with no fill and a red stroke that you can animate with the trim paths option, or just use a radial wipe on the layer with the red line.
BTW, I also have a free clock template on my site that lets you easily animate the motion of the clock hands if you are planning to do that.
Erik Waluska
EAWmedia