Is it worth to use my key for scorched crate?

No

no

Did you plan on trading it or what was the other alternative?

Look on the wiki what is the item that you most like then try to trade the key for it.

you must have the scorched key, not the normal key

I've been very fortunate with S. keys. Use it if you don't have any of the new items.

Trade it for normal keys currnet price is 2 keys :) Then you can buy some game if you will have more