diff --git a/cmd/setup/59.sql b/cmd/setup/59.sql
new file mode 100644
index 0000000000..579d6bd963
--- /dev/null
+++ b/cmd/setup/59.sql
@@ -0,0 +1,33 @@
+-- Add composite indexes to improve introspection endpoint performance
+-- These indexes optimize the queries in introspection_client_by_id.sql
+
+-- Composite index for apps7_api_configs: (instance_id, client_id) 
+-- This speeds up the WHERE clause in the first part of UNION
+CREATE INDEX CONCURRENTLY IF NOT EXISTS apps7_api_configs_instance_client_idx 
+ON projections.apps7_api_configs (instance_id, client_id);
+
+-- Composite index for apps7_oidc_configs: (instance_id, client_id)
+-- This speeds up the WHERE clause in the second part of UNION
+CREATE INDEX CONCURRENTLY IF NOT EXISTS apps7_oidc_configs_instance_client_idx 
+ON projections.apps7_oidc_configs (instance_id, client_id);
+
+-- Composite index for apps7: (instance_id, id, state)
+-- This speeds up the JOIN condition from config to apps7
+CREATE INDEX CONCURRENTLY IF NOT EXISTS apps7_instance_id_state_idx 
+ON projections.apps7 (instance_id, id, state);
+
+-- Composite index for projects4: (instance_id, id, state)  
+-- This speeds up the JOIN condition from apps7 to projects4
+CREATE INDEX CONCURRENTLY IF NOT EXISTS projects4_instance_id_state_idx 
+ON projections.projects4 (instance_id, id, state);
+
+-- Composite index for orgs1: (instance_id, id, org_state)
+-- This speeds up the JOIN condition from projects4 to orgs1
+CREATE INDEX CONCURRENTLY IF NOT EXISTS orgs1_instance_id_state_idx 
+ON projections.orgs1 (instance_id, id, org_state);
+
+-- Composite index for authn_keys2: (instance_id, identifier, expiration)
+-- This speeds up the keys lookup with all filtering conditions
+CREATE INDEX CONCURRENTLY IF NOT EXISTS authn_keys2_instance_identifier_expiration_idx 
+ON projections.authn_keys2 (instance_id, identifier, expiration) 
+WHERE expiration > current_timestamp;
\ No newline at end of file
diff --git a/internal/query/introspection_client_by_id.sql b/internal/query/introspection_client_by_id.sql
index 1cc6baf9ad..83c57386ff 100644
--- a/internal/query/introspection_client_by_id.sql
+++ b/internal/query/introspection_client_by_id.sql
@@ -3,24 +3,25 @@ with config as (
 		from projections.apps7_api_configs
 		where instance_id = $1
 			and client_id = $2
-	union
+	union all
 		select instance_id, app_id, client_id, client_secret, 'oidc' as app_type
 		from projections.apps7_oidc_configs
 		where instance_id = $1
 			and client_id = $2
 ),
 keys as (
-	select identifier as client_id, json_object_agg(id, encode(public_key, 'base64')) as public_keys
+	select $2::text as client_id, json_object_agg(id, encode(public_key, 'base64')) as public_keys
 	from projections.authn_keys2
 	where $3 = true -- when argument is false, don't waste time on trying to query for keys.
 		and instance_id = $1
 		and identifier = $2
 		and expiration > current_timestamp
-	group by identifier
 )
-select config.app_id, config.client_id, config.client_secret, config.app_type, apps.project_id, apps.resource_owner, p.project_role_assertion, keys.public_keys
-from config
-join projections.apps7 apps on apps.id = config.app_id and apps.instance_id = config.instance_id and apps.state = 1
-join projections.projects4 p on p.id = apps.project_id and p.instance_id = $1 and p.state = 1
-join projections.orgs1 o on o.id = p.resource_owner and o.instance_id = config.instance_id and o.org_state = 1
-left join keys on keys.client_id = config.client_id;
+select c.app_id, c.client_id, c.client_secret, c.app_type, 
+       a.project_id, a.resource_owner, p.project_role_assertion, 
+       k.public_keys
+from config c
+join projections.apps7 a on a.id = c.app_id and a.instance_id = c.instance_id and a.state = 1
+join projections.projects4 p on p.id = a.project_id and p.instance_id = c.instance_id and p.state = 1
+join projections.orgs1 o on o.id = p.resource_owner and o.instance_id = c.instance_id and o.org_state = 1
+left join keys k on k.client_id = c.client_id and $3 = true;