SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e0411d26f38366e99d61b3083ab562022d2f1aca817487b9a53340450b194fc' 
  AND token = '5QNYTWt/wBpbl6bAVKSpMqqKmQe9Cixk2sqDkIsmhCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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