SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd242535749d9a11aa3a1d5614260a9a67bb06192d062bb45589e7bc7d29e754d' 
  AND token = '/lMuQRH0nAdz5IGJbbwt3hGldmW8BBvyKPszfBhr8Xk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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