diff --git a/db/migrate/20250507211848_add_index_to_heartbeats.rb b/db/migrate/20250507211848_add_index_to_heartbeats.rb
new file mode 100644
index 0000000..48410d1
--- /dev/null
+++ b/db/migrate/20250507211848_add_index_to_heartbeats.rb
@@ -0,0 +1,7 @@
+class AddIndexToHeartbeats < ActiveRecord::Migration[8.0]
+  def change
+    add_index :heartbeats, [ :user_id, :time ],
+              name: "idx_heartbeats_user_time_active",
+              where: "deleted_at IS NULL"
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index ca5498a..b42a820 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2025_05_07_204732) do
+ActiveRecord::Schema[8.0].define(version: 2025_05_07_211848) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_catalog.plpgsql"
 
@@ -210,6 +210,7 @@ ActiveRecord::Schema[8.0].define(version: 2025_05_07_204732) do
     t.datetime "deleted_at"
     t.index ["category", "time"], name: "index_heartbeats_on_category_and_time"
     t.index ["fields_hash"], name: "index_heartbeats_on_fields_hash_when_not_deleted", unique: true, where: "(deleted_at IS NULL)"
+    t.index ["user_id", "time"], name: "idx_heartbeats_user_time_active", where: "(deleted_at IS NULL)"
     t.index ["user_id"], name: "index_heartbeats_on_user_id"
   end