条件不适用于流明和mongodb

I am using

"jenssegers/mongodb": "3.2.*"

my query is like below,

$query= DB::connection('mongodb')->collection('folder_master')
                ->where('email_account_id',1)->get();

it is not giving me any result though there is value present in database.

if I am using query as below

$query= DB::connection('mongodb')->collection('folder_master')->get();

then it is giving me all the records but where condition is not working.

my expected result is below,

Array
(
    [0] => Array
        (
            [_id] => MongoDB\BSON\ObjectId Object
                (
                    [oid] => 5bea89ac19f043251000347d
                )

            [0] => Array
                (
                    [folder_name] => Archive
                    [status] => Active
                    [primary_folder] => 0
                    [email_account_id] => 1
                    [created_at] => Array
                        (
                            [date] => 2018-11-13 08:22:04.000000
                            [timezone_type] => 3
                            [timezone] => UTC
                        )

                    [created_by] => 0
                )

        )
)

is there any issue while storing in database ????

here is the json which is stored in mongodb

{ 
    "_id" : ObjectId("5bea89ac19f043251000347d"), 
    "0" : {
        "folder_name" : "Archive", 
        "status" : "Active", 
        "primary_folder" : NumberInt(0), 
        "email_account_id" : NumberInt(1), 
        "created_at" : {
            "date" : "2018-11-13 08:22:04.000000", 
            "timezone_type" : NumberInt(3), 
            "timezone" : "UTC"
        }, 
        "created_by" : NumberInt(0)
    }
}

please help me to resolve this type of issue