SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36a561f6fef6919dc9e2d5812cbea25496539be11993f64990b638638c765b7d' 
  AND token = 'ISggekgmx88qPFvlo5MZbOGVAnxeKjwB4rG/s+MJ4js=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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