SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8544c29191e6440f3ffed8dedf87f9e92ec71cde5968edae78ea0d0b630d2688' 
  AND token = 'ObuyFa8jtz6233ngbfi7mfLNiUNBMskXZ6xzqKn3r7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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