SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88bf736dac7e17d31425a6a404641d145140f1885a4da197349fa65f7d7fc17b' 
  AND token = 'hFZleuIjRGF8Xrr485Y33LOOFtGcp5qDbTXSTogFjig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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