I am applying to a graduate school in the USA, and they accept receiving an application during my final year in bachelor's. If I am given admission based only on the previous years of study, will the transcript of the final year, affect in any way after I finish the bachelors?
Once you are accepted it is very unlikely that it would later be rescinded, except for serious breaches. But you won't do yourself any good if you give up your efforts. Your acceptance is probably contingent on successfully completing the bachelors, however. Don't jeopardize that.
On the other hand, don't start grad school in a state of burn out. You are only part way through the race.