Code:
UPDATE products SET metatags_products_name_status = 1 WHERE metatags_products_name_status = 0 AND ...;
Where ... is whatever additional criteria you want to have, such as a products_id, specific master_categories_id, etc... or remove the 'AND ...' at the end to change the setting for all product.

Note though as shags38 pointed out, using a default version of ZC, something that is not empty as associated with php needs to be in either the metatags description or keywords section. If neither has a "truthy" value then the above metatag change will do nothing.