diff --git a/docs/architecture/storage-minimal-contract.md b/docs/architecture/storage-minimal-contract.md
index 86754f85..75eef48d 100644
--- a/docs/architecture/storage-minimal-contract.md
+++ b/docs/architecture/storage-minimal-contract.md
@@ -61,6 +61,7 @@
 6. MySQL realtime 当前态表不保留代理主键和创建时间。
    - 原因：`vehicle_realtime_snapshot`、`vehicle_realtime_location` 都是每协议每 VIN 一行的当前态投影，业务主键就是 `(protocol, vin)`。
    - 状态：schema 使用 `PRIMARY KEY (protocol, vin)`，不保留自增 `id` 和 `created_at`，对外只暴露最新 `updated_at`。
+   - 索引：不在 `vehicle_realtime_location` 维护经纬度组合索引；实时表只回答当前态，地理范围和轨迹类查询走 TDengine 历史位置。
    - 写入：车牌从 `vehicle_identity_binding` 反查时使用 VIN 级短 TTL 内存缓存，避免实时帧每条都打 MySQL；缓存不作为事实来源。
    - 生产：项目上线前可直接重建这两张 MySQL 表，实时数据会从 Kafka 新消息继续投影。
 
diff --git a/go/vehicle-gateway/internal/realtime/snapshot_writer.go b/go/vehicle-gateway/internal/realtime/snapshot_writer.go
index 3b30a458..4a055182 100644
--- a/go/vehicle-gateway/internal/realtime/snapshot_writer.go
+++ b/go/vehicle-gateway/internal/realtime/snapshot_writer.go
@@ -371,8 +371,7 @@ const realtimeLocationTableSQL = `CREATE TABLE IF NOT EXISTS vehicle_realtime_lo
   updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
   PRIMARY KEY (protocol, vin),
   KEY idx_vin (vin),
-  KEY idx_protocol_updated (protocol, updated_at),
-  KEY idx_location (longitude, latitude)
+  KEY idx_protocol_updated (protocol, updated_at)
 )`
 
 const upsertRealtimeLocationSQL = `
diff --git a/go/vehicle-gateway/internal/realtime/snapshot_writer_test.go b/go/vehicle-gateway/internal/realtime/snapshot_writer_test.go
index 6110e411..bda4ec82 100644
--- a/go/vehicle-gateway/internal/realtime/snapshot_writer_test.go
+++ b/go/vehicle-gateway/internal/realtime/snapshot_writer_test.go
@@ -62,6 +62,9 @@ func TestSnapshotWriterEnsuresSchemaAndUpsertsCoreSnapshot(t *testing.T) {
 			t.Fatalf("realtime current-state table should key by protocol/vin: %s", call.query)
 		}
 	}
+	if strings.Contains(exec.calls[1].query, "idx_location") {
+		t.Fatalf("realtime location table should not keep unused geo index: %s", exec.calls[1].query)
+	}
 	upsert := exec.calls[2]
 	if !strings.Contains(upsert.query, "ON DUPLICATE KEY UPDATE") {
 		t.Fatalf("upsert query = %s", upsert.query)