SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f8a8e80724b2899748767a2b380bc7c4bdb63aec6e8906c96107785a4584361' 
  AND token = 'kJBwU+7KbYqkIqFPxwlsZqpgwpSHlOlREtilVFyEBYA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}