SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '712392948ee5f8a1895416e33ab62058ed3f360d1743604fe22e7876bcb180d7' 
  AND token = 'rulYGf8ObiZdpqvq5CwpTqcSoVgWa5RG9ZB/UuB8vhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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