SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28af22c31b200c8c544d5ddeb7a52ac469ee65136cea513dd10f7aaa68c8b5df' 
  AND token = 'zomJpJX66qV+MsaLNzOgObcMZGgs/DuBIUmKnwJSvjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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