SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc49ad0baccde607e210ac3db54766f137df78b76eeb788562bb77c267618f9d' 
  AND token = 'sedPKv28yc0wPZQdtszD1rU+jDXpvV5+SHucgxLr61s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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