diff --git a/app/models/submission_event.rb b/app/models/submission_event.rb
index 2769bcbb..11a6e995 100644
--- a/app/models/submission_event.rb
+++ b/app/models/submission_event.rb
@@ -16,10 +16,11 @@
 #
 # Indexes
 #
-#  index_submission_events_on_account_id     (account_id)
-#  index_submission_events_on_created_at     (created_at)
-#  index_submission_events_on_submission_id  (submission_id)
-#  index_submission_events_on_submitter_id   (submitter_id)
+#  index_submission_events_on_account_id        (account_id)
+#  index_submission_events_on_created_at        (created_at)
+#  index_submission_events_on_submission_id     (submission_id)
+#  index_submission_events_on_submitter_id      (submitter_id)
+#  index_submissions_events_on_sms_event_types  (account_id,created_at) WHERE ((event_type)::text = ANY ((ARRAY['send_sms'::character varying, 'send_2fa_sms'::character varying])::text[]))
 #
 # Foreign Keys
 #
diff --git a/db/migrate/20251121113910_add_send_sms_send_2fa_sms_index.rb b/db/migrate/20251121113910_add_send_sms_send_2fa_sms_index.rb
new file mode 100644
index 00000000..f6f666a8
--- /dev/null
+++ b/db/migrate/20251121113910_add_send_sms_send_2fa_sms_index.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class AddSendSmsSend2faSmsIndex < ActiveRecord::Migration[8.0]
+  def change
+    add_index :submission_events, %i[account_id created_at],
+              where: "event_type IN ('send_sms', 'send_2fa_sms')",
+              name: 'index_submissions_events_on_sms_event_types'
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 16a8d39b..5ceb1f31 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_11_21_093511) do
+ActiveRecord::Schema[8.0].define(version: 2025_11_21_113910) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "btree_gin"
   enable_extension "plpgsql"
@@ -297,6 +297,7 @@ ActiveRecord::Schema[8.0].define(version: 2025_11_21_093511) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.bigint "account_id"
+    t.index ["account_id", "created_at"], name: "index_submissions_events_on_sms_event_types", where: "((event_type)::text = ANY ((ARRAY['send_sms'::character varying, 'send_2fa_sms'::character varying])::text[]))"
     t.index ["account_id"], name: "index_submission_events_on_account_id"
     t.index ["created_at"], name: "index_submission_events_on_created_at"
     t.index ["submission_id"], name: "index_submission_events_on_submission_id"