SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a18c89cd8c008dabc5fc076ac33aa1ef9b1dc3f4b2dfd3abe6636c1665a4da1' 
  AND token = '3RSIBsQCBAtgrvFfH73faY+YnLW0uMEh4MjnhJZopYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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