SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18724931733ea0fce4cbc6e0cb28f86787460dfae6d15b13d686c6e99ef8187d' 
  AND token = 'QDJzYjqELeaA41pZzsmU90TORVC9jULnnjbKvkwuXwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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