“What kind of keys do kids carry?”/“Cookies.”

A pun about cookies is:
 
Q: What kind of keys do kids like to carry?
A: Cookies.
 
The joke has been cited in print since at least 1998.
 
   
Google Books
The Rugrats’ Joke Book
By David Lewman
New York, NY: Scholastic, Inc.
1998
Pg. 19:
What kind of keys does Tommy like to carry?
Cookies.
 
31 January 2006, The Daily Globe (Ironwood, MI), “Kids’ Jokes,” pg. 6, col. 6:
What kind of keys do kids carry?
Cookeys (cookies).
 
Google Books
Family Follies:
A Book of Family Jokes
By Jill L. Donahue, Zachary Trover
Minneapolis, MN: Picture Window Books
2007
Pg. ?:
What kind of keys do kids like to eat?
Cookies.
 
Google Books
Let’s Eat in the Funny Zone
By Gary Chmielewski
Chicago, IL: Norwood House Press
2008
Pg. 21:
What kind of keys do children like to carry?
Cookies.
 
30 August 2010, Titusville (PA) Herald, “Jokes For Kids,” pg. 2, col. 4:
What kind of keys do kids like to carry?
Cookies.
 
Twitter
mariel
‏@harrylovesYSL
WHAT KIND OF KEYS DO KIDS CARRY? .....COOKIES! hahaha yaaay!
8:58 PM - 14 Sep 2010
 
Google Books
The Mammoth Book of Really Silly Jokes:
Humour for the whole family
By Geoff Tibballs
London: Constable & Robinson, Ltd
2011
Pg. 108:
What kind of keys do kids like to carry?
Cookies.
 
Twitter
Josweeny
‏@josweeny
Josweeny’s joke of the day
Q: what kind of keys can you eat?
A: cookies
9:28 AM - 13 Jun 2016