SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd68f4c60ecfaa92fd579ba0a1381c81c53b1ed12978263a35613ce16032a4506' 
  AND token = '7osCyi/xIIWj2ddvodrDLCDj72f+kfYz6mvAf3e4f4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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