Can you pass an exam without studying?
Sometimes, yes. If you already know the subject, the exam is easy, or you get lucky with the questions, you can scrape a pass with zero studying. But it's a bad bet. You're gambling your grade on luck. If you have even an hour, spend it on past papers, the key topics, and testing yourself. That beats walking in cold every time.
Be honest with yourself about why you're asking. If the test is basic, or it's a subject you already use a lot, you might pass on what's in your head. People do it. But you only hear about the ones who got away with it, not the ones who failed. The questions might be exactly what you didn't expect, and then there's no backup plan.
If time is really tight, don't try to read everything. That's how you end up knowing a little about nothing. Pick the few topics that show up the most and the ones worth the most marks. Most courses repeat the same big ideas, so a past paper or two will show you fast what actually gets asked.
Then test yourself instead of re-reading. Close the notes and try to write out the answer from memory. You'll feel dumb at first, but that's the point, the stuff you blank on is exactly what you need to fix. This is called active recall and it sticks way better than reading the same page five times. An hour of this beats a whole night of highlighting.