SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '023802a759bf699dcdf22b4414d94715df2d2148eea1079c2deb231d836aa271' 
  AND token = 'K/w5ahLlCgeqvIOJf/YPHBKFzU0GUCW4T59pDu2SmrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00085

JSON explain

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