SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38ab38089ebad3d6188fa9f9fd1cdecd28599f01e04f13a5a32298f98ad40bdd' 
  AND token = 'RfdMo5yYeij1Zrol3XgJYEUBSOqxmHYTqKh9HkFOCmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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