SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47c9835fa97284002e6191b8eff50b64e6e8c0063c19836b4b005b34d5361bdd' 
  AND token = 'H6nBt97q7uxNDILlvS23LQp9OrtmkT0hcbXoAGVWF2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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