SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81940f5d13fc8046f519bc7d91b507b8db181698ea2595bb20be9788dac18a90' 
  AND token = 'r0a41oQyt9lMcYJvQUv19uVK2gg1urWG0SoXWjHYc6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}