Status bar > Time controls > Next Frame
Keyboard > . (period)
Next Frame moves the time slider ahead one frame.
If Key Mode is on, the time slider moves to the next keyframe. Keyframe options are set in the Key Steps group of the Time Configuration dialog. If Use TrackBar is turned on, Next Frame will jump to the next key of any kind. If Use TrackBar is turned off, then Next Frame will jump to the next transform key, ignoring any other type of keys.