If it is by 6AM then expect to pay extra charges but that also comes down to room availability. My office messed up my flight and hotel booking I arrived like very early at the hotel like 12-13 hours early, I was tired and was ready to pay for an extra night just to get into my room for a hot bath and quick nap but guess what they had zero availability, I gave them my luggage and slept in the lobby itself. I was so deep in sleep snoring and what not that they decided to send their staff to wake me up and thankfully assigned me one of their higher category, initially asked me to pay extra 50% for early check-in which I was ok with but upon sharing my number it turned out I was a privilege member, So they waived that extra 50% off and said some other random stuff I couldn't understand. So check beforehand if you have some kind of membership with the brand that may help you get early check-in.