SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '238346b8c0fbab88f95bfbf790da2b03452f610c1ff3520eb3b3ebc2cb9124b9' 
  AND token = 'osPRHryAnAtJfOTp3XNceAQv+tB8T5iWzAE3XpAbZH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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