Yes it is. 3D secure has no such requirement. It simply requires transactions get forwarded thorough your bank's site. How they handle these is up to them.

Here in the UK, most are auto approved without any input. Amex will sometimes text and email you a code. Lloyd's will often, and bizarrely, ask you to enter details from the card (this is near useless from a security point of view and as much hassle as a secure one time code).