SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16d0a2741f4ebbcb972c8efd5ccff50b72b7f34f4bc7242fe2850629ca7cc6b0' 
  AND token = 'QM4ONzKADuMD/DoQIEvoQoOmYnx2carmFy8hGUlPmik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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