SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '190606a489bfeabd57964c3bd5f8d3b232a957d41b7f714a84fc838c24e529d9' 
  AND token = 'eDwVDzrzGjVcaiv8wxiRcKchKijARdL3xhv7JDRpd+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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