SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e46844bf0d4992bc7aafccfffb71802dcfdd1e679b5ffe3fa27133a8700a163d' 
  AND token = '5kcteH56ssGpkjWw8uh1lu8BtQNqwRy0VDCN6LnUyK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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