I have a key starting with underscore and don't know how to query it
aws dynamodb query \
--table-name mytable \
--key-condition-expression '_mykey=:xxx' \
--expression-attribute-values '{ ":xxx": {"S": "somevalue"}}'
An error occurred (ValidationException) when calling the Query operation: Invalid KeyConditionExpression: Syntax error; token: "_", near: "_mykey"
Can I escape it somehow? I tried "/_mykey" and "\_mykey" but doesn't work.