SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '406cc2073e5855a7fde58901aeb903f745d54df77b58efb2c660174508dea65d' 
  AND token = 'VKkC8NyTVRCsrZ88dt0ByfRAcNUEoSvOaQMbb98ssX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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