SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73b335757e027f9e50f6a3c05868b9111927f986673f19c5fb291021dd41cd57' 
  AND token = '0KVaRb0mjCax5pP6vNJevUO+QVNtBgFfUmgbaBhS0Xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}