Is it possible to put an if statement into the scripted expression of a driver? If the y location of a certain object is greater than 0, I want to add a fixed amount to another object's driven channel. How do I achieve that?
A Python expression you can use is:

valueIfTrue if isConditionTrue else valueIfFalse


This is known as a ternary conditional operator see:
https://stackoverflow.com/questions/394809/ternary-conditional-operator-in-python