SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72157953596f316b84c8b25e14c6b2dffa2fee24ddbf2317cc640081c40bd98f' 
  AND token = '7xEbhyVrxlZx+mkMnOngCeZ9m3gVX1s1duZZZs7ZLic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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