SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad9762f8626163a8b3dd9c9169d7dbf5e6e304db7fa4fb1422cf5f82a7ebc2ba' 
  AND token = 'eYShcC8V17Ei6/U47t2wCZU6tjjBM0NFvndthxvqNiw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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