SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c84f3e28288bd7ee7f30c39ad94b473a51499cf764f362dc9d66670b87746b9' 
  AND token = 'H6721WC4onMFfeHyMQss+0mRNw/JA6GtgZn1iqdOJw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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