Database

[{"ID":"290283667","Data":{"Product-2713890":{"Created":ISODate("2016-08-23T20:55:39.437Z"),"Product":"Product-2713890"}}}]

Query

db.collection.aggregate([{$addFields:{hashmaps:{$objectToArray:"$$ROOT.Data"}}},{$project:{"ID":1,"hashmaps":{$arrayElemAt:["$hashmaps",0]}}},{$project:{"ID":1,"Product":"$hashmaps.k","Created":{$dateToString:{format:"%Y-%m-%d %H:%M:%S",date:"$hashmaps.v.Created"}}}}])

Result