Click the “Add a variable” action in the edit query UI.
If scheduledAt is not in that list, then there is no schedule data available to that part of your flow.
If the Scheduled time trigger is directly connected to what has this issue, probably try and hard reload the shopify flow url; and test in a different browser.
Since we can’t attach flows files here, an example flow JSON, save contents unformatted to a file with .flow extension to import into shopify flow:
Schedule customer query to Log output.flow
2fc8ff5c92cad7781b93dfe43c01e98567082a5352ccc08dc9aab72491ff9ef7:{"__metadata":{"version":0.1},"root":{"steps":[{"step_id":"0e8b3d00-a363-11ee-afa6-bf6712f80a55","step_position":[900,1240],"config_field_values":[{"config_field_id":"recurrence","value":"[\"DTSTART;TZID=America/New_York:20231225T120000\\nRRULE:FREQ=HOURLY;INTERVAL=1;WKST=MO\"]"}],"task_id":"shopify::flow::scheduled_time","task_version":"0.1","task_type":"TRIGGER","description":null,"note":null,"name":null},{"step_id":"1528a8a0-a363-11ee-afa6-bf6712f80a55","step_position":[1260,1240],"config_field_values":[{"config_field_id":"sort_by","value":"{\"sortKey\":\"CREATED_AT\",\"order\":\"ASCENDING\"}"},{"config_field_id":"max_root_records","value":"10"},{"config_field_id":"query","value":"customer_date:<='{{ scheduledAt }}' AND customer_date:>'{{ scheduledAt | date_minus: \"1 week\" }}'\n"}],"task_id":"shopify::flow::fetch::customers","task_version":"v1","task_type":"ACTION","description":null,"note":null,"name":"Get customer data"},{"step_id":"273db7b0-a363-11ee-afa6-bf6712f80a55","step_position":[1620,1240],"config_field_values":[{"config_field_id":"message","value":"{% for getCustomerData_item in getCustomerData %}\n {{getCustomerData_item.email}}\n{% endfor %}\n\n{{ getCustomerData | json }}\n"}],"task_id":"shopify::flow::print","task_version":"0.1","task_type":"ACTION","description":null,"note":null,"name":null}],"links":[{"from_step_id":"0e8b3d00-a363-11ee-afa6-bf6712f80a55","from_port_id":"output","to_step_id":"1528a8a0-a363-11ee-afa6-bf6712f80a55","to_port_id":"input"},{"from_step_id":"1528a8a0-a363-11ee-afa6-bf6712f80a55","from_port_id":"output","to_step_id":"273db7b0-a363-11ee-afa6-bf6712f80a55","to_port_id":"input"}],"workflow_name":"Schedule customer query to Log output"}}