Hello if you use the Kendo Upload wrapper for MVC the antiforgery will be send automatically to the server.
Since you are using the old extensions you might need to use the OnUpload event to manually find that value and send it to the server.
e.g.
function onMyUpload(e){
e.data = { "__RequestVerificationToken": $('input[name=__RequestVerificationToken]').val() };
}