SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '897bde5c8b494c4d45244906c7a3023c5b693124310ad92581da1b33bc1f74ce' 
  AND token = 'PY+8We1lOzY/EGvCRMyig2RtSiAnm+ZhfSmmj1Jf40Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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