SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd4daa9897d201378bc65d7644cc9721ee7c481a867c8e23bac24f6d61ad81b3' 
  AND token = 'f68o62EiAzsOWuPOek81uJzPnLbSXrQS82il2OioE84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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