If the revocation was successful you will get an HTTP response code of 200 back from the EVE SSO.
As described in https://tools.ietf.org/html/rfc7009#section-2.2, a 200 response code from the revocation endpoint is not confirmation that the token was revoked, and will be returned even if an invalid token was sent to the endpoint.
The final instruction in https://github.com/esi/esi-docs/blob/master/docs/sso/revoking_refresh_tokens.md says:
As described in https://tools.ietf.org/html/rfc7009#section-2.2, a 200 response code from the revocation endpoint is not confirmation that the token was revoked, and will be returned even if an invalid token was sent to the endpoint.
The docs should be updated to make this clearer.