SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d8247b7894a6d5e6954c66fbc527d79312a3d1e2e36fbf76029f87815b2b868' 
  AND token = 'zUWXaA/7xrXWrgdZve4QycpW2m+Rl/15jPzbI1/ZduQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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