Hello

Yes, you can apply for CET exams in both states.
You are eligible to apply for MHT-CET since you completed 12th from Maharashtra, but without a Maharashtra domicile, you’ll be considered an Outside Maharashtra (OMS) candidate.
You can also apply for KCET because you studied 10th in Karnataka, but state quota benefits depend on domicile and years of study, not just exam location.
Simply appearing in the exam is allowed in both states. However, reservation and state quota seats depend on each state's domicile rules.