SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be8d9dc77517c5a55e9bc7dd058291fe45e892084eb9a9aec8ce3c3c989e2e67' 
  AND token = 'prK1MabPPvwyvpZIncbBI6uwr8DvRvTrLhGHJ7s3Neo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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