SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '337bb05aef5e80668363ebc911ea31e90037e68e95a1b54f53204824d8f7ceb5' 
  AND token = 'XB3AkoeMS7uunz6nPZBrTVo+9W4ila2a0MuQt4vo71k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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