SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9b770f74290ab3bcab212b1c9bae12834ff6e4bd841675f21e5540f24c54f8f' 
  AND token = 'KLDGer8T/Hzb2D26VF+bgXpXaRFtTlSVgUA3sMhvPEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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