SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '01f91f82364d9fbaaddefeb7d262dabf7460b0108984d9732345da7df74fc34f' 
  AND token = 'wbhtZ0t6DG+PUJXLp2AwARgoFZh3K+JpYVI2AcVHcy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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