SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd90c20499170850e8a17585d37b6d966dda398fa5549d79bfb36a0d805c3ca55' 
  AND token = '+t0dWIcQLqVAdOVpt2k29zWBw1XDavWbnb9pqPSNO4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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