SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '798da4ce0815a69561733ef4daddebe9394355cce4b160001b4d23924337be7b' 
  AND token = 'QpUo0TvL2Y5DdtRuL58CDN+S6KLaZ1HCE1bRa+mL7kQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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