SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '818e26269a79965dd837d422a5da77726fd3ba51ac4ff5a7089a54ab1168b916' 
  AND token = 'ZGbf0XWfkpBwehugo6pn+8eyjYbigkxvO+AXXh7gPmk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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