1: Use lower case letters in the search placeholder text: "Enter keyword or product code..." OR
2: Change to "Search products or brands"
Capitalisation is not expected or required here and adds unnecessary emphasis. If anything, the search box as a whole needs to be emphasised.
'Brands' is more suggestive than 'Keywords' and more likely to trigger an effective search.
Product codes are not visible anywhere on product pages. Unless users are retrieving product codes from catalogs and searching online, the 'product code' placeholder text might not be of any value at all.
The Search box seems to only index product titles and brands. It does not seem to index text under 'Product Information', i.e. actual keywords users are likely to use, e.g. "100% cotton black polo shirt". Therefore, 'Keywords' is not an effective placeholder text either.