diff --git a/src/mibew/libs/classes/Mibew/Settings.php b/src/mibew/libs/classes/Mibew/Settings.php
index 1bc712e2..8fe82d1d 100644
--- a/src/mibew/libs/classes/Mibew/Settings.php
+++ b/src/mibew/libs/classes/Mibew/Settings.php
@@ -53,11 +53,8 @@ Class Settings {
 
 	/**
 	 * Settings class constructor. Set default values and load setting from database.
-	 * @global $default_cron_key Default value for cron security key. Defined
-	 * in libs/common/constants.php
 	 */
 	protected function __construct() {
-		global $default_cron_key;
 		// Set default values
 		$this->settings = array(
 			'dbversion' => 0,
@@ -107,7 +104,7 @@ Class Settings {
 			'invitation_lifetime' => 60, /* Lifetime for invitation to chat */
 			'tracking_lifetime' => 600, /* Time to store tracked old visitors' data */
 
-			'cron_key' => $default_cron_key,
+			'cron_key' => DEFAULT_CRON_KEY,
 
 			// System values are listed below. They cannot be changed via
 			// administrative interface. Start names for these values from
diff --git a/src/mibew/libs/common/constants.php b/src/mibew/libs/common/constants.php
index 78b299fa..ca598115 100644
--- a/src/mibew/libs/common/constants.php
+++ b/src/mibew/libs/common/constants.php
@@ -40,10 +40,10 @@ define('SESSION_PREFIX', md5($mysqlhost.'##'.$mysqldb.'##'.$mysqlprefix) . '_');
  * Default value for cron security key.
  * Another value can be set at operator/settings.php page.
  */
-$default_cron_key = md5(
+define('DEFAULT_CRON_KEY', md5(
 	$mysqlhost . '##' . $mysqldb . '##' . $mysqllogin. '##' .
 	$mysqlpass . '##' . $mysqlprefix . '##'
-);
+));
 
 /**
  * Name for cookie to track visitor