Hello @Tetralink, no, converting the environment to a production environment will not impact the licensing requirements.
In your case, though, I would consider creating an additional environment. If I understood you correctly, you are currently developing your application in the sandbox environment. The best practice would be to export this application as part of a managed solution and import it into a separate production environment.
That way you can continue to make changes in the sandbox environment without affecting your production app. Whenever you're ready, you can move your updated and tested app to the production environment.
This will not have an impact on licensing.
If you want to learn more about this, here is more information about solutions.