SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44ceafea1d893245ec9b3e67391d78e80c3b9044958f2d0ae6424c1943449564' 
  AND token = 'EJrWSnZqb++SsWCmTvuW5A+7FiyVkUFbmbvN2xvtYp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}