SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57cb7b52731a5d1119d43c2bf2e70c35d639a73b9955cb27a6bb496a983fd53e' 
  AND token = 'a+aXqcKT4JG+uBwLZc4O/WdBlqdd2lVmv1Rnhq+J31g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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