SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff6890d6863232140974581101f036e6ba5b74f42abf1d74868725e5eaec2a17' 
  AND token = 't9HxNYoxFtwNZ1K7LM/n3er1OZLrZjh01qVdrgN/THo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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