SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '296979fe45138d7fe19159cb87afbbb2d4a82dde8195cf945758b876c48cec98' 
  AND token = '8pPzsXWpYAdMAUkaoAyUxpX/hEKBfHM4oSp3tLwx2UQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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