diff --git a/app/dao/broadcast_service_dao.py b/app/dao/broadcast_service_dao.py
index 546b6ed91..6166b0634 100644
--- a/app/dao/broadcast_service_dao.py
+++ b/app/dao/broadcast_service_dao.py
@@ -70,7 +70,8 @@ def set_broadcast_service_type(service, service_mode, broadcast_channel, provide
 
     # Revoke any API keys to avoid a regular API key being used to send alerts
     ApiKey.query.filter_by(
-        service_id=service.id
+        service_id=service.id,
+        expiry_date=None,
     ).update({
         ApiKey.expiry_date: datetime.utcnow()
     })
diff --git a/tests/app/service/test_rest.py b/tests/app/service/test_rest.py
index a74ff05c9..b8a27c00f 100644
--- a/tests/app/service/test_rest.py
+++ b/tests/app/service/test_rest.py
@@ -4172,6 +4172,7 @@ def test_set_as_broadcast_service_removes_user_permissions(
     assert service_user.get_permissions(service_id=sample_service_full_permissions.id) == ['send_emails']
 
 
+@freeze_time('2021-12-21')
 def test_set_as_broadcast_service_revokes_api_keys(
     admin_request,
     broadcast_organisation,
@@ -4179,7 +4180,10 @@ def test_set_as_broadcast_service_revokes_api_keys(
     sample_service_full_permissions,
 ):
     api_key_1 = create_api_key(service=sample_service)
-    api_key_2 = create_api_key(service=sample_service_full_permissions)
+    api_key_2 = create_api_key(service=sample_service)
+    api_key_3 = create_api_key(service=sample_service_full_permissions)
+
+    api_key_2.expiry_date = datetime.utcnow() - timedelta(days=365)
 
     admin_request.post(
         'service.set_as_broadcast_service',
@@ -4190,5 +4194,12 @@ def test_set_as_broadcast_service_revokes_api_keys(
             'provider_restriction': 'all',
         }
     )
-    assert api_key_1.expiry_date < datetime.utcnow()
-    assert api_key_2.expiry_date is None
+
+    # This key should have a new expiry date
+    assert api_key_1.expiry_date.isoformat().startswith('2021-12-21')
+
+    # This key keeps its old expiry date
+    assert api_key_2.expiry_date.isoformat().startswith('2020-12-21')
+
+    # This key is from a different service
+    assert api_key_3.expiry_date is None