SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f12f970dce6a16a85e0f098596865d1f11a793e94dc3285d91202d7bf1693127' 
  AND token = '0E/Ai/my5HVwBh9nRqQMUt4i39hwu65OfoU/bWaAMPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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