How to optimize getting data from mysql via php / android?

Introduction

I have an app and want to force the user to update it, if a new version is at the google play market. This is working fine with the following code but is not very stable. I am doing it via AsyncTask and getting data from the php file. But it gives me a feeling that there must be a better way or a way that makes it much more stable.

Question

How can I set a timeout to the procedure, for example because of a very low internetconnection from the user?

Code

get_newest_apk.php

<?PHP

    /*  GET APK VERSION FROM ANDROID DEVICE
        Example: [PATH]/get_newest_apk.php?apkversion=6
    */
    if($_GET["apkversion"]){
        $apkversion= $_GET["apkversion"];

        //MYSQL LOGIN PARAMETERS
        $host = '*****';
        $user = '*****';
        $pass = '*****';
        $db =   '*****';

        $mysqli = new mysqli($host, $user, $pass, $db);

            $result = $mysqli->query("SELECT MAX(VERSION) FROM TBL_APK");
            $row = $result->fetch_row();
            $count = $row[0];

            if($count > $apkversion){
                //Newer APK is avaiable
                echo "1";
            }else{
                //There is no never APK avaiable
                echo "2";
            }

    }else{
        //Error by GETTING apkversion from Android device
        echo "3";
    }
?>

AsyncTask Class

class checkForNewAPK extends AsyncTask<Void, Void, String> {
    @Override
    protected void onPreExecute() {
        //Do not show the user a progress because he don't want to see it in every onResume
    }

    @Override
    protected void onPostExecute(String s) {
        super.onPostExecute(s);
        int intResult = Integer.parseInt(s);

        //strResult as intResult; 1 = Newer APK avaiable, 2 = No newer APK avaiable, 3 = Error at $_GET["apkversion"] line 6
        if(intResult == 1){
            //Force to Update App
            Log.v("APKResult: ", "1");
        }else if(intResult == 2){
            //No update needed
            Log.v("APKResult: ", "2");
        }else if(intResult == 3){
            //Error in PHP-File
            Log.v("APKResult: ", "3");
        }else{
            //Unknown error
            Log.v("APKResult: ", "Unkown Error");
        }
    }

    //in this method we are fetching the json string
    @Override
    protected String doInBackground(Void... voids) {
        try {
            int intApkVersion = getApplication().getPackageManager().getPackageInfo(getPackageName(), 0).versionCode;
            URL url = new URL(strUrlGetNewestAPK+"?apkversion="+intApkVersion);
            String strResultFromEcho;

            HttpURLConnection con = (HttpURLConnection) url.openConnection();
            StringBuilder strResult = new StringBuilder();

            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));
            while ((strResultFromEcho = bufferedReader.readLine()) != null) {
                strResult.append(strResultFromEcho + "\n");
            }

            return strResult.toString().trim();
        } catch (Exception e) {
            return null;
        }
    }
}

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