diff --git a/lib/backend/dynamo/dynamodbbk.go b/lib/backend/dynamo/dynamodbbk.go
index 3aef1d04b7c2d..44772550310a9 100644
--- a/lib/backend/dynamo/dynamodbbk.go
+++ b/lib/backend/dynamo/dynamodbbk.go
@@ -837,7 +837,7 @@ const (
 // prependPrefix adds leading 'teleport/' to the key for backwards compatibility
 // with previous implementation of DynamoDB backend
 func prependPrefix(key backend.Key) string {
-	return keyPrefix + string(key)
+	return keyPrefix + key.String()
 }
 
 // trimPrefix removes leading 'teleport' from the key
diff --git a/lib/backend/dynamo/dynamodbbk_test.go b/lib/backend/dynamo/dynamodbbk_test.go
index 0688990279d77..ce0420e00f1fc 100644
--- a/lib/backend/dynamo/dynamodbbk_test.go
+++ b/lib/backend/dynamo/dynamodbbk_test.go
@@ -29,6 +29,7 @@ import (
 	"github.com/gravitational/trace"
 	"github.com/jonboulle/clockwork"
 	log "github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	"github.com/gravitational/teleport/lib/backend"
@@ -214,3 +215,21 @@ func TestCreateTable(t *testing.T) {
 		})
 	}
 }
+
+func TestKeyPrefix(t *testing.T) {
+	t.Run("leading separator in key", func(t *testing.T) {
+		prefixed := prependPrefix(backend.NewKey("test", "llama"))
+		assert.Equal(t, "teleport/test/llama", prefixed)
+
+		key := trimPrefix(prefixed)
+		assert.Equal(t, "/test/llama", key.String())
+	})
+
+	t.Run("no leading separator in key", func(t *testing.T) {
+		prefixed := prependPrefix(backend.Key(".locks/test/llama"))
+		assert.Equal(t, "teleport.locks/test/llama", prefixed)
+
+		key := trimPrefix(prefixed)
+		assert.Equal(t, ".locks/test/llama", key.String())
+	})
+}
diff --git a/lib/backend/etcdbk/etcd.go b/lib/backend/etcdbk/etcd.go
index 68e0e7267f668..02cd015e7c1fc 100644
--- a/lib/backend/etcdbk/etcd.go
+++ b/lib/backend/etcdbk/etcd.go
@@ -1016,10 +1016,10 @@ func fromType(eventType mvccpb.Event_EventType) types.OpType {
 	}
 }
 
-func (b *EtcdBackend) trimPrefix(in backend.Key) backend.Key {
-	return in.TrimPrefix(backend.Key(b.cfg.Key))
+func (b *EtcdBackend) trimPrefix(in []byte) backend.Key {
+	return backend.Key(in).TrimPrefix(backend.Key(b.cfg.Key))
 }
 
 func (b *EtcdBackend) prependPrefix(in backend.Key) string {
-	return b.cfg.Key + string(in)
+	return b.cfg.Key + in.String()
 }
diff --git a/lib/backend/etcdbk/etcd_test.go b/lib/backend/etcdbk/etcd_test.go
index df1f76f1326ef..bd48c7184be3d 100644
--- a/lib/backend/etcdbk/etcd_test.go
+++ b/lib/backend/etcdbk/etcd_test.go
@@ -26,6 +26,7 @@ import (
 
 	"github.com/gravitational/trace"
 	"github.com/jonboulle/clockwork"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	"github.com/gravitational/teleport/lib/backend"
@@ -255,3 +256,29 @@ func etcdTestEndpoint() string {
 	}
 	return "https://127.0.0.1:2379"
 }
+
+func TestKeyPrefix(t *testing.T) {
+	prefixes := []string{"teleport", "/teleport", "/teleport/"}
+
+	for _, prefix := range prefixes {
+		t.Run("prefix="+prefix, func(t *testing.T) {
+			bk := EtcdBackend{cfg: &Config{Key: prefix}}
+
+			t.Run("leading separator in key", func(t *testing.T) {
+				prefixed := bk.prependPrefix(backend.NewKey("test", "llama"))
+				assert.Equal(t, prefix+"/test/llama", prefixed)
+
+				key := bk.trimPrefix([]byte(prefixed))
+				assert.Equal(t, "/test/llama", key.String())
+			})
+
+			t.Run("no leading separator in key", func(t *testing.T) {
+				prefixed := bk.prependPrefix(backend.Key(".locks/test/llama"))
+				assert.Equal(t, prefix+".locks/test/llama", prefixed)
+
+				key := bk.trimPrefix([]byte(prefixed))
+				assert.Equal(t, ".locks/test/llama", key.String())
+			})
+		})
+	}
+}
diff --git a/lib/backend/helpers.go b/lib/backend/lock.go
similarity index 100%
rename from lib/backend/helpers.go
rename to lib/backend/lock.go
diff --git a/lib/backend/helpers_test.go b/lib/backend/lock_test.go
similarity index 88%
rename from lib/backend/helpers_test.go
rename to lib/backend/lock_test.go
index 496c476d674ca..822ede66236f0 100644
--- a/lib/backend/helpers_test.go
+++ b/lib/backend/lock_test.go
@@ -21,9 +21,24 @@ import (
 	"time"
 
 	"github.com/google/go-cmp/cmp"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
+func TestLockKey(t *testing.T) {
+	t.Run("empty parts", func(t *testing.T) {
+		key := lockKey()
+		assert.Equal(t, ".locks", key.String())
+		assert.Equal(t, [][]byte{[]byte(".locks")}, key.Components())
+	})
+
+	t.Run("with parts", func(t *testing.T) {
+		key := lockKey("test", "llama")
+		assert.Equal(t, ".locks/test/llama", key.String())
+		assert.Equal(t, [][]byte{[]byte(".locks"), []byte("test"), []byte("llama")}, key.Components())
+	})
+}
+
 func TestLockConfiguration_CheckAndSetDefaults(t *testing.T) {
 	type mockBackend struct {
 		Backend