SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9a1da9280f6dbb20d265cf1b5e9b18b437a93566591eff459f75faa7718a538' 
  AND token = 'UiPnuV0/pdXqlRtMS9Q7ZVzlOKj54SSCcpVNSCHwpdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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