Querying an array of arrays in MongoDB

Say, I have a document like this..

{
  "ID" : "fruit1",
  "Keys" : [["apple", "carrot", "banana"]]
}

How do I query for Keys = "carrot". None of the following syntax works.

db.myColl.results.find({ "Keys" : "carrot" });
db.myColl.results.find({ "Keys" : [["carrot"]] });

Following works though, but not helpful.

db.myColl.results.find({ "Keys" : [["apple", "carrot", "banana"]]});

Any pointer to this query will be helpful. Thanks.