So I locked my keys in my 2010 Lexus LS460 and i noticed this big middle button on thr trunk lid, should I press it?

If you can reach them its worth a shot. A better option is calling Lexus road side assistance. They may be able to come out and help you or give you a trick over the phone that will work. In some cases they can remote unlock the car. Alex

you only have one key,no spare key?

Call locksmith!