SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6302615d961966fd76e62f5cbc36a4d1a126c6c476c09d10762ae0beea49fbcd' 
  AND token = '/Dboo3Wi9WVim0uX5gxSjO9Iva5iJZumZvfK072JlMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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