No, the e-vignette obligation starts the moment you enter a tolled motorway, even if you plan to exit immediately.
If you get caught driving without a valid e-vignette you will be subject to a heavy fine.
You can now comfortably order your Czech e-vignette here.
Related articles:
What happens if I drive without a Czech e-vignette?
Can I drive into the Czech Republic without a valid e-vignette if I avoid motorways?
What different types are available for the Czech e-vignette?