SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '915e067fa50d30ea7d325d9c1b4eaa3f63fcd2753eb0f9fec59bb9d95ee767cc' 
  AND token = 'Yh+qV4MjbBXlhcaw06WgNyrOv45gUKxwcQMxpzNef40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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