SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc1b7fd33eaa31d111601e8599d02698ea16f4427fee8f726c5dd117bd67afda' 
  AND token = 'LVBZh2XiI//6+qCcbX3EOqDGbZ2LiHW1TqVpKyUIk40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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