SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30e143cce183b297bb1eaf30f4182531897a776edb815723aee0fa098e2adf33' 
  AND token = '+tvcZUSIxtrB8dNnDGWWdweXWjrUDUeZW19BnABOgG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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