Providing previous/next keyframe buttons would enable quick navigation between keyframes.
For each property:
Left arrow: Previous keyframe in that property
Right arrow: Next keyframe in that property
A 'special' Previous / Next arrow (or hot key) that takes you to the previous/next keyframe for an element regardless of what property that keyframe is for. (Perhaps next to the element name in the Timeline list or a dedicated line at the bottom of the property section.)
Inspiration: Final Cut Pro's 'Motion' window keyframe nagivation.