SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71f67197305acad013edf71fe58ddbebcff2870c9a6b61b4adeb7eec80225ff1' 
  AND token = 'IDjw0vuBtXPhoYMt6TTkEIVnU3gYad27HexflBsXOVI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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