Function unlocked_and_recent_instances 

pub fn unlocked_and_recent_instances(
    db: &BlockchainDatabase,
    tx_ro: &Snapshot,
    tapes: &TapesReadTransaction<'_>,
    amount: Amount,
    total_instances: u64,
    current_height: u64,
    recent_cutoff: u64,
) -> DbResult<(u64, u64)>

Compute (unlocked_instances, recent_instances) for an output amount.