Your key is sent here too, so it is not lost if you close this page.
Paid in crypto — you choose the coin next. Your licence key appears once the network confirms the payment, usually 15–30 minutes. It is kept on your account, so you can close this page.
You go straight to that coin's payment page. The key appears on your account once the network confirms the payment, usually 15–30 minutes — Bitcoin can take longer than Litecoin.
It is kept on your account under "Your keys", where you can use it whenever you like.