i've got two allergic dogs at home and if the licking is due to an allergie, your dog will lick alot almost fanatic. the white fur on the paws (if your dog has any white fur there) will turn red if your dog has red fur there the fur will turn dark purple, the paws are moist between the toes and the skin there will have turned red, they will smell (i don't know if i would describe it as popcorn though), light claws will turn red to puprple and almost black beginning at the socket of the claw, the dog might get dinges between the toes that will get infected and become open sores. all those are symptomes of athlete's foot, which dog's get when having allergies, mostly against some food source, propably a proteine source. if your dog is allergic to something he eats he might aswell have stomache troubles such as diarrhea, he might have thin fur on his head or pimples between his legs and/or in his face. however, your dog will dislike you taking or touching his paws trying to draw them from you grip, if the licking is due to athlete's foot caused by an allergie. a blod test and a scrape test on his skin can determine if it is an allergie and what kind of allergie it is.
but licking and athlete's foot can also be due to if a lot of salting is done on the roads (against ice and snow). if it is the case that they use a lot of salt in winter (if you have any snow where you live), than the problem will disappear in spring. during winter time you should wash you dog's paws after every walk in that case.
if it's because of boredom try to activate you dog a bit more ;)