Just take photo with it and see if the result is what you like. If you like, scratches won't make you hate it, right?
In case you don't like it (e.g low contrast, flare due to the scratch, etc), try the same lens without scratch to compare. You never know until you try, you may not even like the mint version
My Canon 50f1.4 is pretty scratched up on the front element but no noticable deterioration on the IQ. My previous 35 titanium lux pre-asph on the other hand was badly hazed that resulted in flare. I sold it at a loss.
On the contrary, my 50 f1.2 is really minty with some coating gone at the tip of the front element. Read online some filter will touch that portion. Looks like previous filter not that compatible. I am using Leica E55 UV/IR filter. Looks ok to me.
It would depend on the depth of the scratch. If it's only the coating that was scratched, usually you won't notice the effect. Flares may appear. When the optic is breach, that's when you get more distraction.