Sorry to reply almost a decade later - but Key Brand Shoes were a brand of Shoes from the Giesecke, D'Oench, and Hayse shoe company. Giesecke and D'Oench were brother-in-laws who had on again and off again partnerships in shoe companies between 1871 and 1910. The later iterations of the company end up becoming Red Goose Shoes (around 1906). Pronouncing the name Giesecke - you get both the key sound and the geese sound in them (a geese and a Key). The earlies Red Goose promotions had a key in the Goose's mouth.
Do you still have the box? My wife is related to the Gieseckes and the D'Oenches and loves to collect their stuff. Even if you don't want to part with the box, could you send a photo? Thanks.