SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '999500495263bcddffcd8f02754ed7e345aaa68b4947a83514cd9e001418f00b' 
  AND token = 'DChqDlT4k4IquRp/+vkXDBqfXcwCfJN2dYHWc940f9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00127

JSON explain

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