SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90ab6c2a2f7ac731f0120a6cc15363c9b13f0735959d3da557d7559dfb94840b' 
  AND token = '4AAexTGHlJfNHcqXBHKMa6eIffYt6v2qIoB95jXxDpU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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