to a specific point in time - position the timeline cursor at the beat point/time on the timeline where you want to zoom into then you use the + and - for both vertical and horizontal zooming and the slider controls to scroll up/down and left/right
or
Using the Magnifier tool - see image below for the options available when you right click it - note this also tells you the keyboard shortcuts.
Left click on the Magnifier tool resets the zoom level to normal.