diff --git a/swh/auth/django/utils.py b/swh/auth/django/utils.py
--- a/swh/auth/django/utils.py
+++ b/swh/auth/django/utils.py
@@ -80,7 +80,8 @@
     user = oidc_user_from_decoded_token(decoded_token, client_id=oidc_client.client_id)
 
     # get authentication init datetime
-    auth_datetime = datetime.fromtimestamp(decoded_token["auth_time"])
+    auth_time = decoded_token.get("auth_time", decoded_token["iat"])
+    auth_datetime = datetime.fromtimestamp(auth_time)
     exp_datetime = datetime.fromtimestamp(decoded_token["exp"])
 
     # compute OIDC tokens expiration date
diff --git a/swh/auth/pytest_plugin.py b/swh/auth/pytest_plugin.py
--- a/swh/auth/pytest_plugin.py
+++ b/swh/auth/pytest_plugin.py
@@ -102,13 +102,18 @@
         if userinfo is not None:
             decoded = {**decoded, **userinfo}
         # tweak auth and exp time for tests
-        expire_in = decoded["exp"] - decoded["auth_time"]
+        auth_time = decoded.get("auth_time", decoded["iat"])
+        expire_in = decoded["exp"] - auth_time
         if self.exp is not None:
             decoded["exp"] = self.exp
-            decoded["auth_time"] = self.exp - expire_in
+            auth_time = self.exp - expire_in
+            decoded["iat"] = auth_time
+            decoded["auth_time"] = auth_time
         else:
-            decoded["auth_time"] = int(datetime.now(tz=timezone.utc).timestamp())
-            decoded["exp"] = decoded["auth_time"] + expire_in
+            now = int(datetime.now(tz=timezone.utc).timestamp())
+            decoded["iat"] = now
+            decoded["auth_time"] = now
+            decoded["exp"] = now + expire_in
         decoded["groups"] = self.user_groups
         decoded["aud"] = [self.client_id, "account"]
         decoded["azp"] = self.client_id
diff --git a/swh/auth/tests/sample_data.py b/swh/auth/tests/sample_data.py
--- a/swh/auth/tests/sample_data.py
+++ b/swh/auth/tests/sample_data.py
@@ -18,18 +18,19 @@
     "sub": "feacd344-b468-4a65-a236-14f61e6b7200",
 }
 
+IAT = 1614786418
+EXP = IAT + 300
 
 # Decoded token (out of the access token)
 DECODED_TOKEN = {
     "jti": "31fc50b7-bbe5-4f51-91ef-8e3eec51331e",
-    "exp": 1614787019,
+    "exp": EXP,
     "nbf": 0,
-    "iat": 1582723101,
+    "iat": IAT,
     "iss": "http://localhost:8080/auth/realms/SoftwareHeritage",
     "aud": [CLIENT_ID, "account"],
     "typ": "Bearer",
     "azp": CLIENT_ID,
-    "auth_time": 1614786418,
     "session_state": "d82b90d1-0a94-4e74-ad66-dd95341c7b6d",
     "acr": "1",
     "allowed-origins": ["*"],
diff --git a/swh/auth/tests/test_keycloak.py b/swh/auth/tests/test_keycloak.py
--- a/swh/auth/tests/test_keycloak.py
+++ b/swh/auth/tests/test_keycloak.py
@@ -82,9 +82,9 @@
 
     actual_decoded_data2 = copy(actual_decoded_data)
     expected_decoded_token = copy(DECODED_TOKEN)
-    for dynamic_valued_key in ["exp", "auth_time"]:
-        actual_decoded_data2.pop(dynamic_valued_key)
-        expected_decoded_token.pop(dynamic_valued_key)
+    for dynamic_valued_key in ["exp", "iat", "auth_time"]:
+        actual_decoded_data2.pop(dynamic_valued_key, None)
+        expected_decoded_token.pop(dynamic_valued_key, None)
 
     assert actual_decoded_data2 == expected_decoded_token