For reference, let's see what the original JSON would look like, with pretty formatting:

>>> print(json.dumps(my_json, indent=4))
{
    "name": "ns1:timeSeriesResponseType",
    "declaredType": "org.cuahsi.waterml.TimeSeriesResponseType",
    "scope": "javax.xml.bind.JAXBElement$GlobalScope",
    "value": {
        "queryInfo": {
            "creationTime": 1349724919000,
            "queryURL": "http://waterservices.usgs.gov/nwis/iv/",
            "criteria": {
                "locationParam": "[ALL:103232434]",
                "variableParam": "[00060, 00065]"
            },
            "note": [
                {
                    "value": "[ALL:103232434]",
                    "title": "filter:sites"
                },
                {
                    "value": "[mode=LATEST, modifiedSince=null]",
                    "title": "filter:timeRange"
                },
                {
                    "value": "sdas01",
                    "title": "server"
                }
            ]
        }
    },
    "nil": false,
    "globalScope": true,
    "typeSubstituted": false
}

That lets us see the structure of the data more clearly.

In the specific case, first we want to look at the corresponding value under the 'value' key in our parsed data. That is another dict; we can access the value of its 'queryInfo' key in the same way, and similarly the 'creationTime' from there.

To get the desired value, we simply put those accesses one after another:

my_json['value']['queryInfo']['creationTime'] # 1349724919000

I recommend using the awesome requests library:

import requests

url = 'http://maps.googleapis.com/maps/api/directions/json'

params = dict(
    origin='Chicago,IL',
    destination='Los+Angeles,CA',
    waypoints='Joplin,MO|Oklahoma+City,OK',
    sensor='false'
)

resp = requests.get(url=url, params=params)
data = resp.json() # Check the JSON Response Content documentation below

JSON Response Content: https://requests.readthedocs.io/en/master/user/quickstart/#json-response-content

You can use list comprehension and dict like this:

device_disco["device"] =[dict(username=k1["username"],password=k1["password"],ip=k1["ip"]) for k1 in 
device_disco["device"]]

jsonData = json.dumps(device_disco)
print (jsonData)

in your code:

import requests
import json

#API request details
url = 'api url'
data = '{"service":"ssh", "user_id":"0", "action":"read_by_user", 
"user":"D2", "keyword":"NULL"}'
headers = {"Content-Type": "application/json"}

#Making http request
response = requests.post(url,data=data,headers=headers,verify=False)
print(response)

#Json string
json_disco = response.text
print(type(json_disco))
print(json_disco)

#Decode response.json() method to a python dictionary and use the data
device_disco = response.json()
print(type(device_disco))
print(device_disco)
device_disco["device"] =[dict(username=k1["username"],password=k1["password"],ip=k1["ip"]) for k1 in 
device_disco["device"]]

jsonData = json.dumps(device_disco)


with open('devices.json', 'w') as fp:
json.dump(jsonData, fp, indent=4, sort_keys=True)

Use it as a dictionary.

a = page.json()
print a['tradeId']

Since you're using requests, you should use the response's json method.

import requests

response = requests.get(...)
data = response.json()

It autodetects which decoder to use.

Short Answer

To answer your question no, you can't but to understand why you need to know what is happening behind the scenes.

Behind the scenes

When you make a request such as r = requests.get('www.foo.bar') you are making a request to the server and you are viewing the result of that request when you do r.json(). This means that you cannot just get r[3]['data'] as you are parsing what the server sends to you unless the server only sends r[3]['data']. It may be possible to filter out everything else apart from that in the response processing but I am unaware of how to do it.