Here's another variation to try:

=SUM(IF($D$1:$BC$1=Now(),D2:BC2,0))

This is an array formula, so when you have typed it in (and if you
subsequently edit it) use CTRL-SHIFT-ENTER rather than just ENTER - if
you do this correctly then Excel will wrap curly braces { } around the
formula. You should not type these yourself.

You can copy the formula down if you wish.

Hope this helps.

Pete