SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '175a89477d023c81caa0f64733ca887c327b4098fda7ae4ee221bb71d2662303' 
  AND token = 'U+JU+bLeWPHgX5Rbrx9S21dNo8N7wgQoFgtb+it2Yik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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