SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70dc6af7a6314713dc4809bfc3dda59a6f8a9acb2e6e74c0666832caa0db277d' 
  AND token = 'rJ5tHl1iHWA5P1MJ3WWzRcUqv03DdNQyxKOqYgzs0cQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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