SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f474432b1804412cd29e9577298a105c7f615481b5b7bd68c95177c9deb91db8' 
  AND token = 'AgKCFcMELb3FuM1X0U5sVdSOF3XF/S0HOLJ2NZDikeI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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