SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f62a0ed79d55fdcb580f9cce563920b88a25ecd4d264afc2d920868cdebab254' 
  AND token = 'Yp5SM4wzcGtCh2AWXOFe149lyYxUHKQO9JM95xtIwBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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