SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9404680f03204b1020acd80985dcb45b257a697a442efccf1600abbb9930f0a6' 
  AND token = 'hgSBsIKMUVprRaG32zv2rrmwmv6VrkFgffB37KukeJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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