SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb53c6fc810971bfc3e9db62dae9f9f19936625c993658f793b1813092f6f840' 
  AND token = 'SMmpXdWDlnNHy9zjeuAjMELdS/B0XK5va3PnrnbrMlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}