SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1303c5456ac7bb36edc82a742a5601004b6e94eebf8ce198f54021443aea8a27' 
  AND token = 'JX61/RrJpHEvBxhufjlgbyBbhg6C9HYIhka4VkrHDSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}