SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b995621dd5e33fb0684fe2532bd918ff5cf0646b7f9d2f54f8ca43e0494bffde' 
  AND token = 'R3qsB67vGBJvXP7fYHKhQtMEoBh//Ritb2PuL7IYZ38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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