SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65c4663ec7fef79a76f7cbd8b6fb38a2a1ea0cfefb630cfe2da6755b49f08cb6' 
  AND token = 'mT0oSj4wCe+7huXxxa4UHpeVfTmt9NuGxJ4esH3HkRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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