diff --git a/pom.xml b/pom.xml
index 4c327f5..3b05762 100644
--- a/pom.xml
+++ b/pom.xml
@@ -55,7 +55,7 @@
         <dependency>
             <groupId>org.assertj</groupId>
             <artifactId>assertj-core</artifactId>
-            <version>3.6.2</version>
+            <version>3.9.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>
diff --git a/src/main/java/okra/OkraSyncImpl.java b/src/main/java/okra/OkraSyncImpl.java
index f086fed..b79738e 100644
--- a/src/main/java/okra/OkraSyncImpl.java
+++ b/src/main/java/okra/OkraSyncImpl.java
@@ -29,7 +29,6 @@
 import okra.base.sync.AbstractOkraSync;
 import okra.exception.InvalidOkraItemException;
 import okra.exception.OkraItemNotFoundException;
-import okra.exception.OkraRuntimeException;
 import okra.index.IndexCreator;
 import okra.serialization.DocumentSerializer;
 import okra.util.DateUtil;
@@ -37,6 +36,8 @@
 import org.bson.Document;
 import org.bson.conversions.Bson;
 import org.bson.types.ObjectId;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.time.LocalDateTime;
 import java.util.Date;
@@ -50,6 +51,7 @@ public class OkraSyncImpl<T extends OkraItem> extends AbstractOkraSync<T> {
     private final Class<T> scheduleItemClass;
     private final long defaultHeartbeatExpirationMillis;
     private final DocumentSerializer serializer;
+    private static final Logger LOGGER = LoggerFactory.getLogger(OkraSyncImpl.class);
 
     public OkraSyncImpl(final MongoClient client, final String database,
                         final String collection, final Class<T> scheduleItemClass,
@@ -78,8 +80,7 @@ public Optional<T> poll() {
 
     @Override
     public Optional<T> peek() {
-        final Bson peekQuery = QueryUtil.generatePeekQuery(defaultHeartbeatExpirationMillis);
-
+        final Bson peekQuery = QueryUtil.generatePeekQuery(defaultHeartbeatExpirationMillis / 1000);
         final Document update = new Document();
         update.put("heartbeat", new Date());
         update.put("status", OkraStatus.PROCESSING.name());
diff --git a/src/main/java/okra/util/QueryUtil.java b/src/main/java/okra/util/QueryUtil.java
index 43248bc..a047025 100644
--- a/src/main/java/okra/util/QueryUtil.java
+++ b/src/main/java/okra/util/QueryUtil.java
@@ -44,7 +44,7 @@ public static Document generateRunDateQueryPart() {
     public static Document generateStatusProcessingAndHeartbeatExpiredQuery(final long secondsToGetExpired) {
         final Document query = new Document();
         query.put("status", OkraStatus.PROCESSING.name());
-        query.put("heartbeat", DateUtil.nowMinusSeconds(secondsToGetExpired));
+        query.put("heartbeat", new BasicDBObject("$lt", DateUtil.nowMinusSeconds(secondsToGetExpired)));
         return query;
     }
 
diff --git a/src/test/resources/testcontainers.properties b/src/test/resources/testcontainers.properties
new file mode 100644
index 0000000..71f1d22
--- /dev/null
+++ b/src/test/resources/testcontainers.properties
@@ -0,0 +1 @@
+checks.disable=true
\ No newline at end of file