SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b3471533d430faaeaa13c55e85554d960903dbf8b3bac027fb0798cf4f2bfe9' 
  AND token = 'tyYOHtFonmVOdJPF2KuoNUx0v+00WHCj+PCILlXehvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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