diff --git a/lib/backend/firestore/firestorebk.go b/lib/backend/firestore/firestorebk.go
index a60946e35770a..8fce65ab248ec 100644
--- a/lib/backend/firestore/firestorebk.go
+++ b/lib/backend/firestore/firestorebk.go
@@ -762,12 +762,23 @@ func (b *Backend) purgeExpiredDocuments() error {
 			return b.clientContext.Err()
 		case <-t.C:
 			expiryTime := b.clock.Now().UTC().Unix()
-			docs, err := b.svc.Collection(b.CollectionName).Where(expiresDocProperty, "<=", expiryTime).Documents(b.clientContext).GetAll()
+			// Find all documents that have expired, but EXCLUDE
+			// any documents that do not have an expiry as indicated
+			// by a value of 0.
+			docs, err := b.svc.Collection(b.CollectionName).
+				Where(expiresDocProperty, "<=", expiryTime).
+				Where(expiresDocProperty, ">", 0).
+				Documents(b.clientContext).
+				GetAll()
 			if err != nil {
 				b.Logger.WithError(trail.FromGRPC(err)).Warn("Failed to get expired documents")
 				continue
 			}
 
+			if len(docs) == 0 {
+				continue
+			}
+
 			if err := b.deleteDocuments(docs); err != nil {
 				return trace.Wrap(err)
 			}