SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f48d33c1f42dfd417a6a96d0f8f19f875829a10916f9503232e271b4d035895a' 
  AND token = 'YTwplG+uiFLDEhHjDhzJRXoYeZ+YXTqsV+Oqi8UiqJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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