SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dc2a5edd4075495b605ce6fdf9e50f8bf663ddf4da385b3b8b671d1180b9e34' 
  AND token = 'V0YaTQ+HpHfAQQeZvhxXYERgOgiRaA3qiHwFEG1BOqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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