SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7643962ee5300f12255f92e545bce1ab8a82c855b060936f1e96bdb48c7cff9' 
  AND token = '1rupWsCI0llSXuYlzZd/ARZsjKIx4VPYTlejnYYEkFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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