I'm a bit doubtful of this, but stranger things have happened. First off, ked doesn't much look like a Gaelic word, but I'm sure Hibernicus can fill us in on that. The only Irish word for tick I could find is sceartán (var. sciortán). I looked around under cead and ceid but to no avail. Here's an etymology of sneakers I found online. Seems that Keds were manufactured by US Rubber. I wore Keds as a child, but they looked like tennis shoes to me. I've always liked the British term plimsolls.

http://www.wordwizard.com/clubhouse/founddiscuss1.asp?Num=4031