My suggestion would be a combination of nicael's answer and psubee2003's comment:
Whatever interface moderators use to lock questions should have the option to provide a link to a Meta post where the question is being discussed. The wording would change slightly:
This post has been locked while disputes about its content are being resolved. For more info, see: < link to relevant meta post >
If the moderator locking the question doesn't provide a link to a Meta post, the wording would be the same, but the link would point to the What is a locked post? question on MSO. This implementation would require a one-time change of wordiing, but from then on would just require a default link incluson when one isn't provided, so I think it would be simple for the SE team to implement (no new dialogs to write code for).
visit meta
link could point to the exact post that is discussing the content (if one exists). The first time I clicked that link to see what the discussion was about, I was disappointed to find it just took me to the front page of MSO