diff --git a/src/servers/src/prom.rs b/src/servers/src/prom.rs
index 7b9e59564c..eacdfbf1ee 100644
--- a/src/servers/src/prom.rs
+++ b/src/servers/src/prom.rs
@@ -351,20 +351,34 @@ impl PromJsonResponse {
 
 #[derive(Debug, Default, Serialize, Deserialize, JsonSchema)]
 pub struct InstantQuery {
-    query: String,
+    query: Option<String>,
     time: Option<String>,
     timeout: Option<String>,
+    db: Option<String>,
 }
 
 #[axum_macros::debug_handler]
 pub async fn instant_query(
-    State(_handler): State<PromHandlerRef>,
-    Query(_params): Query<InstantQuery>,
+    State(handler): State<PromHandlerRef>,
+    Query(params): Query<InstantQuery>,
+    Form(form_params): Form<InstantQuery>,
 ) -> Json<PromJsonResponse> {
-    PromJsonResponse::error(
-        "not implemented",
-        "instant query api `/query` is not implemented. Use `/query_range` instead.",
-    )
+    let time = params.time.or(form_params.time).unwrap_or_default();
+    let prom_query = PromQuery {
+        query: params.query.or(form_params.query).unwrap_or_default(),
+        start: time.clone(),
+        end: time,
+        step: "1s".to_string(),
+    };
+
+    let db = &params.db.unwrap_or(DEFAULT_SCHEMA_NAME.to_string());
+    let (catalog, schema) = super::parse_catalog_and_schema_from_client_database_name(db);
+
+    let query_ctx = QueryContext::with(catalog, schema);
+
+    let result = handler.do_query(&prom_query, Arc::new(query_ctx)).await;
+    let metric_name = retrieve_metric_name(&prom_query.query).unwrap_or_default();
+    PromJsonResponse::from_query_result(result, metric_name).await
 }
 
 #[derive(Debug, Default, Serialize, Deserialize, JsonSchema)]
diff --git a/tests-integration/tests/http.rs b/tests-integration/tests/http.rs
index 74e417b1f1..831a9a9b16 100644
--- a/tests-integration/tests/http.rs
+++ b/tests-integration/tests/http.rs
@@ -290,11 +290,16 @@ pub async fn test_prom_http_api(store_type: StorageType) {
     let client = TestClient::new(app);
 
     // instant query
-    let res = client.get("/api/v1/query?query=up").send().await;
+    let res = client.get("/api/v1/query?query=up&time=1").send().await;
     assert_eq!(res.status(), StatusCode::OK);
-    let res = client.post("/api/v1/query?query=up").send().await;
+    let res = client
+        .post("/api/v1/query?query=up&time=1")
+        .header("Content-Type", "application/x-www-form-urlencoded")
+        .send()
+        .await;
     assert_eq!(res.status(), StatusCode::OK);
 
+    // range query
     let res = client
         .get("/api/v1/query_range?query=up&start=1&end=100&step=5")
         .send()