SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8aab4852c147f20a714ce788dacafc50a6cad28b7b9e5bbcf073af0c1ec2dc8d' 
  AND token = 'oAZ0IQq+5coWQRI/wubcinSSspcMuJpLXoGVN+jk5Fo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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