diff --git a/packages/cryptography/src/Timelock.php b/packages/cryptography/src/Timelock.php
index 30eb757860..d8eefc97b8 100644
--- a/packages/cryptography/src/Timelock.php
+++ b/packages/cryptography/src/Timelock.php
@@ -29,7 +29,7 @@ public function __construct(
     public function invoke(callable $callback, Duration $duration): mixed
     {
         $exception = null;
-        $start = microtime(as_float: true);
+        $start = $this->clock->timestamp();
 
         try {
             $result = $callback($this);
@@ -37,7 +37,7 @@ public function invoke(callable $callback, Duration $duration): mixed
             $exception = $thrown;
         }
 
-        $remainderInMicroseconds = intval($duration->getTotalMicroseconds() - ((microtime(true) - $start) * 1_000_000));
+        $remainderInMicroseconds = intval($duration->getTotalMicroseconds() - $this->clock->timestamp()->since($start)->getTotalMicroseconds());
 
         if (! $this->canReturnEarly && $remainderInMicroseconds > 0) {
             $this->clock->sleep(Duration::microseconds($remainderInMicroseconds));
diff --git a/tests/Integration/Cryptography/TimelockTest.php b/tests/Integration/Cryptography/TimelockTest.php
index 5619a2ff67..64462215ea 100644
--- a/tests/Integration/Cryptography/TimelockTest.php
+++ b/tests/Integration/Cryptography/TimelockTest.php
@@ -17,7 +17,7 @@ public function uses_mocked_clock(): void
 
         $ms = $clock->timestamp()->getMilliseconds();
         $timelock->invoke(
-            callback: fn () => null,
+            callback: fn () => usleep(1_000),
             duration: Duration::milliseconds(10_000),
         );
         $elapsed = $clock->timestamp()->getMilliseconds() - $ms;