Date range query for past 24 hour in Mongo shell
Found answer here:
https://stackoverflow.com/questions/1296358/subtract-days-from-a-date-in-javascript

db.system.profile.find({ 
  "timestamp" : { 
    $lt: new Date(), 
    $gte: new Date(new Date().setDate(new Date().getDate()-1))
  }   
})