SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0db8b7064a79249bb05026f5727bd0defd52101370590b4d9fb3e3296e055a2b' 
  AND token = 'A8wlcEWJ8hkUDaoX8EYoOvhkVfryzZz7y3XMADYL2VA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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