SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bb38acfaa66659080fb669bcef840a3238e29be9dfbf63ca07f5f67ebaf2e3f' 
  AND token = '6GJzsSzSnyGz/cY8XWje3r0uiTVd1/IuIU4XiZNe8MY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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