SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da60f29a88c65dba8c6a2d444a361497fa6f09c534c950575bbdb7700973765b' 
  AND token = 'jWVxvX6uAd54P1JgS3UXwmp/JbZVYia+XwjkplDtMzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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