SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a55e9b1f392bfc497c0f480f45d13922d613bd7355cd4dfcadc484109295b4cc' 
  AND token = 'jdb6JuusjI7I8qcUFjVt5rNNY9mqSzoVNjWMdYqpCQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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