SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6bf9c1fb5c73dff762e3af946d680516a9e7ee5032022734b269a62ea446528a' 
  AND token = 'xvkXlxO+Zyf+pglQGPDggbQFGZi3AjzuCrAtXnlBnWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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