SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e407965f8ed78cde3f75c0fcd257cd57d8a9f82361289baf453dd88167826057' 
  AND token = 'fWAcHD5YTTlGaRrji+Hqe5Un36UwwIiECB2HZg7ClmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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