diff --git a/src/backend/base/langflow/services/database/models/api_key/model.py b/src/backend/base/langflow/services/database/models/api_key/model.py
index e3780be67..9937e7e73 100644
--- a/src/backend/base/langflow/services/database/models/api_key/model.py
+++ b/src/backend/base/langflow/services/database/models/api_key/model.py
@@ -11,7 +11,7 @@ if TYPE_CHECKING:
 
 class ApiKeyBase(SQLModel):
     name: Optional[str] = Field(index=True, nullable=True, default=None)
-    created_at: datetime = Field(sa_column=Column(DateTime(timezone=True), server_default=func.now()))
+    created_at: datetime = Field(sa_column=Column(DateTime(timezone=True), server_default=func.now(), nullable=False))
     last_used_at: Optional[datetime] = Field(default=None, nullable=True)
     total_uses: int = Field(default=0)
     is_active: bool = Field(default=True)
diff --git a/src/backend/base/langflow/services/database/models/variable/model.py b/src/backend/base/langflow/services/database/models/variable/model.py
index b473b08d3..e197ba1e3 100644
--- a/src/backend/base/langflow/services/database/models/variable/model.py
+++ b/src/backend/base/langflow/services/database/models/variable/model.py
@@ -26,7 +26,7 @@ class Variable(VariableBase, table=True):
     )
     # name is unique per user
     created_at: datetime = Field(
-        sa_column=Column(DateTime(timezone=True), server_default=func.now()),
+        sa_column=Column(DateTime(timezone=True), server_default=func.now(), nullable=False),
         description="Creation time of the variable",
     )
     updated_at: Optional[datetime] = Field(