Performing the following (note the range of 10,000):

`importmulti '[{"desc": "sh(wpkh([aeee1e6a/49h/1h/0h]tpubDC5bVdaveQYxGFztMShFAjU637kKjrs9FD8ne1oHR7z8tLeQJExsaxWRVeSpcCcYMdp5ecf2LQhuVaeYFZ7YEpvWTJr4nDGUJrmuvLuTSsp/1/*))", "keypool": true, "timestamp": "now", "watchonly": true, "internal": true, "range": {"end": 1000}}]' '{"rescan": false}'`

takes many minutes. @achow101 reports a similar import taking 6 minutes on his machine.
{
    bool fLabelFound = false;
    CKey key;
    pwallet->GetKey(keyid, key);
    for (const auto& dest : GetAllDestinationsForKey(key.GetPubKey())) {
        if (pwallet->mapAddressBook.count(dest)) {
            if (!strAddr.empty()) {
                strAddr += ",";
            }
            strAddr += EncodeDestination(dest);
            strLabel = EncodeDumpString(pwallet->mapAddressBook[dest].name);
            fLabelFound = true;
        }
    }
    if (!fLabelFound) {
        strAddr = EncodeDestination(GetDestinationForKey(key.GetPubKey(), pwallet->m_default_address_type));
    }
    return fLabelFound;
}
static const int64_t TIMESTAMP_MIN = 0;
static void RescanWallet(CWallet& wallet, const WalletRescanReserver& reserver, int64_t time_begin = TIMESTAMP_MIN, bool update = true)
{
    int64_t scanned_time = wallet.RescanFromTime(time_begin, reserver, update);
    if (wallet.IsAbortingRescan()) {
        throw JSONRPCError(RPC_MISC_ERROR, "Rescan aborted by user.");
    } else if (scanned_time > time_begin) {
        throw JSONRPCError(RPC_WALLET_ERROR, "Rescan was unable to fully rescan the blockchain. Some transactions may be missing.");
    }
}
UniValue importprivkey(const JSONRPCRequest& request)