SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99e3026eadfd3372dda610aa03243e52ea7d6999ad78edfdfa4e5ccf8278feae' 
  AND token = 'njJLqiUfhBYKZmQu9hk/28ixc847+8WjTci/wPzy3cw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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