To recover google photos from lost phone, just install google photos app on your new mobile and login with the same id as you did on lost phone. Once you login, check whether you have all your photos there. Because Google Photos are cloud based back up, so it wont depend on phone storage.

Even though you lost your phone, google photos has all those pictures, if you dont have new phone yet, just open chrome on your laptop or computer. And login browse photos.google.com and sign in with your email Id. Here also you will see your google Photos , you are backed up through your lost phone.