How many hours to be online here for 1usd?

There is no answer to this question! MyLot doesn't pay by the hour. It depends only on how many responses, comments, likes &c. other people give your discussions, responses and comments. It's up to you how much time you spend and whether what you post attracts interaction or not. If what you post is not intersting or worthwhile, you will earn very little, however much time you spend!