The most common meanings of the Key card are success, the ability to solve issues and more times than not guaranteed results. When I see this card in a layout I know that somehow the situation will reach a resolution. The Lenormand cards work together so take a look at the group surrounding the Key card.
Also, keep in mind what you might be asking the cards if anything at all. The meanings are stand-alone when doing the near/far technique which most readers do not use as a daily common practice. There is another set of meanings with this technique and you may find some of the meanings differ but not by much.
The obvious suggestion is that the Key card opens & closes something. It could be a door, a treasure box, a diary, a vehicle, a security box, filing cabinet, a jukebox, etc. The Key also opens and closes situations around a person.
There are various styles of keys from the old fashioned skeleton ones to the modern ones. The key to a problem, situation or person involved is not necessarily visible. When you understand the Key card’s role in the layout you can provide a fairly accurate prediction.
Wherever the Key card falls in the layout it is an indication that a logical or practical solution is within the client’s grasp. The nature of this solution is in the opening or closing of the information surrounding the Key card.