You can use 여세요 or 열어요 What time do you open? 몇시에 문 여세요(열어요)? Are you open? 열었어요(열려있어요)?

What time do you open? 몇시에 (가게 which could mean a store or a restaurant) 여세요? Are you open now? 지금 (가게) 열었어요?