SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4884bcba9179afad4715916cd227b46fed5737ce9d58ee65fbbb50581dff6e3b' 
  AND token = 'q3LH7S0XAP1YkKUhNpd+h6QePYbkzDa6Y7Jt4YoP8g0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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