Optimize IsAdminFilter and prevent checking empty from_user field

filters/admin.py

@@ -1,6 +1,6 @@
 from aiogram.filters import BaseFilter
 from aiogram.types import CallbackQuery, Message
-from sqlalchemy import select
+from sqlalchemy import select, exists
 
 from database.db import async_session_maker
 from database.models import Admin
@@ -8,10 +8,14 @@ from database.models import Admin
 
 class IsAdminFilter(BaseFilter):
     async def __call__(self, event: Message | CallbackQuery) -> bool:
+        if not event.from_user:
+            return False
+
         try:
             async with async_session_maker() as session:
-                result = await session.execute(select(Admin).where(Admin.tg_id == event.from_user.id))
-                admin = result.scalar_one_or_none()
-                return admin is not None
-        except Exception:
+                result = await session.execute(
+                    select(exists().where(Admin.tg_id == event.from_user.id))
+                )
+                return result.scalar()
+        except (Exception,):
             return False