Tokig can mean "crazy", "mad", "nuts" or "silly". In this case silly, I would say. There are many words that start with "tok" such as "tokstolle", "tokskalle", "toktroll", "tokunge". I've never used or heard "tokfrans" to be honest. "Frans" can mean either "Fabric fray", or "eyelash" or maybe even the name "Frans". It sounds like a nonsensical expression that would be used when talking, or referring, to a child. Like in English when they say "you silly goose".