1. A system for identifying items that satisfy dimensional criteria specified by a user, the system comprising: an electronic data storage system comprising one or more databases that each store item keys that are sorted, wherein each item key is associated with one or more item identifiers, wherein each item identifier identifies a corresponding item from a plurality of items; and a computing system comprising one or more hardware computing devices executing specific computer-executable instructions, said computing system in communication with the electronic data store, and configured to at least: receive a search request transmitted by a user computing device associated with a user, the search request including an image that depicts a physical space, one or more search terms, and information indicative of the user's interest in placing one or more items associated with the one or more search terms within the physical space, wherein the physical space is at least partially bound by one or more objects depicted in the image; analyze the image to determine dimensional criteria of the physical space, wherein the dimensional criteria comprise a length, a width, a height, or a volume of the physical space; generate one or more composite search keys based at least in part on the dimensional criteria of the physical space and the one or more search terms, wherein each composite search key includes two or more of the length, width, height, or volume of the physical space in a particular order; identify, based at least on the one or more composite search keys, a first set of item keys stored in the one or more databases, wherein an individual item key includes two or more dimension values in the particular order and is associated with one or more item identifiers that each identify a corresponding item associated with the two or more dimension values; determine a set of items that satisfy the dimensional criteria, wherein determining the set of items includes: identifying candidate items based at least on each one of the candidate items being associated with at least one item key in the first set and removing any duplicative candidate items; and output the determined set of items for presentation to a user.