SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39389649f2f2baa468e2dd74df6ea56c466f71cea8440150403cd062da3ffeee' 
  AND token = 'xCjK2BT3cC+bp1bqkXvTPbRc4yWin4wOXOCEsRds/ZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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