SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b6162f24761bdfcce047b5a762b30eb3479b7eaf68521507f45a79eb63ba167' 
  AND token = 'DXej/nw+5RYQYQRl1TNE0n5Z7Y+ovJRwzwgCikmuWCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}