SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd465747d7de43e36937ca306813e3c7dd04b8972f1a7291206dc19539d6dc52c' 
  AND token = 'y+WpBQMKss0iITAY0ZcU0SWdXKCs2kLrGIv15cAAjXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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