I've been thinking the same thing from Michigan in the US.

Edit to provide "how it works":

• After buying THIS ONE (below) the first product was defective.
• So I self-returned and reordered a 2nd product from Amazon assuming because it was new that Quality might improve.
  
• 2nd product works well. So quality did improve.
• I leave the heat setting at 100 degrees which according to my thermometer produces 80 degrees on the pad.
• This keeps my keyboard and track pad comfortable in 60 degree F office!

Amazon (US) has:

• desk heating pad that might work. Actually, there are many. I just bought THIS ONE searching on "heated keyboard" brings up several products
• And they have a
  • heated computer mouse pad hand warmer!
  • heated optical mouse!

here you go!