SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '387aef775f0180d561e60cff55959287537c52be92fdafafed6ed204ac7b13e1' 
  AND token = 'yXK/1N1YdnbZQMPxwDFDBHjblg0jFBhsSKrHZqbopWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00093

JSON explain

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