Welcome, @KurtLohse.
I think you can find belts online - do a google search for "belt for CD players"..., or on eBay, with a search for your particular model CD player.
Check out this listing - it says "SD/A 490t, however, the SD/A 450 shares the same transport mechanism, and hence use the same belt. I've had both of these units, and have even transplanted the drives back and forth between the two models - so this belt "should" work for you.
Online belt sellers may be available, for less money and lower shipping costs. A google search for the size below from the info that @BobTFM35 shared above.
Google AI reports that this belt is often called the following (referenced from TheCarverSite!
"
A 0.046" square x 2.4" (often referred to as an SBS 2.4 or small square 2.4-inch) rubber drive belt is a standard replacement size used for the tray loading and opening mechanisms in various vintage CD players and changers.
"
Check out this website: https://vintageaudioparts.zohocommerce.com/categories/square_belts/2151798000005844097
Look for this belt.
You could try any number of "assortments" of belts on Amazon, here: Amazon.com : SBS 2.4 cd player belt but unfortunately, most sellers list all kinds of models..., but not Carver..., and then offer large "kits" of lots of belts - which one might fit.
Best of luck! Let us know how your repair goes, and don't forget to clean off all the goo that the old belt likely left behind.