How to set x-hasura-admin-secret/x-hasura-access-key

pointed to my Heroku instance

$ node index.js

Err
{ extensions: { path: '$', code: 'start-failed' },
message:
'cannot start as connection_init failed with : x-hasura-admin-secret/x-hasura-access-key required, but not found' }

But x-hasura-admin-secret is already set inside Heroku?

How do we set x-hasura-admin-secret from within nodejs? Tried dotenv package and included in .env file
x-hasura-admin-secret=MY_SECRET

But still same as above?

EDIT: this only works if I remove security from Hasura GraphQL engine? Namely HASURA_GRAPHQL_ADMIN_SECRET is removed, but of course zero security