SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '884fc1fe02f0984ac9b67a085afd2587dd4f65f3775f409a321e54e29ec70a1b' 
  AND token = 'fANiP3GZpaztRkWjg5SJKBWl7BBjdOIUxBbpjnq8Frw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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