The MongoDB currentOp command to help you find all the operations running longer than 300 milliseconds.

currentOp-long-running-ops.js

db.adminCommand({
 "currentOp": true,
 "microsecs_running" : {"$gte" : 300000}
})
/*
// output for the above command 
{
  "inprog": [{
    "host": "shyam-macbook.local:27017",
    "desc": "conn",
    "threadId": "0x70000a805000",
    "connectionId": 3807,
    "client": "127.0.0.1:52818",
    "appName": "MongoDB Shell",
    "clientMetadata": {
      "application": {
        "name": "MongoDB Shell"
      },
      "driver": {
        "name": "MongoDB Internal Client",
        "version": "3.6.2"
      },
      "os": {
        "type": "Darwin",
        "name": "Mac OS X",
        "architecture": "x86_64",
        "version": "17.5.0"
      }
    },
    "active": true,
    "currentOpTime": "2018-05-16T15:20:22.253-0500",
    "opid": 835646,
    "secs_running": NumberLong(0),
    "microsecs_running": NumberLong(343179),
    "op": "update",
    "ns": "guidebook.restaurants",
    "command": {
      "q": {

      },
      "u": {
        "$inc": {
          "visitor_count": 1
        }
      },
      "multi": true,
      "upsert": false
    },
    "planSummary": "COLLSCAN",
    "numYields": 400,
    "locks": {
      "Global": "w",
      "Database": "w",
      "Collection": "w"
    },
    "waitingForLock": false,
    "lockStats": {
      "Global": {
        "acquireCount": {
          "r": NumberLong(401),
          "w": NumberLong(401)
        }
      },
      "Database": {
        "acquireCount": {
          "w": NumberLong(401)
        }
      },
      "Collection": {
        "acquireCount": {
          "w": NumberLong(401)
        }
      }
    }
  }],
  "ok": 1
}
*/