SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd713fcd68cb6c8fedd08c9fa9f6ffd996fa517ec52b7f89c338a13832e9632c8' 
  AND token = 'XGQ6msaIFVpU2ZULq3V6epB+g7HFnNYKPrrVh2LzXMI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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