diff --git a/src/Mysql/PDO.php b/src/Mysql/PDO.php
index f8a0ec2..24f34de 100644
--- a/src/Mysql/PDO.php
+++ b/src/Mysql/PDO.php
@@ -98,7 +98,7 @@ class PDO implements StopHeartbeatCheck
 	 */
 	public function stopHeartbeatCheck(): void
 	{
-		if (Context::inCoroutine()) {
+		if ($this->_timer > -1) {
 			Timer::clear($this->_timer);
 		}
 		$this->_timer = -1;