SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '669b482027ebb7246966db1a23a4de0ba08c777a069a293977bf17f2b3844be4' 
  AND token = 'cBFbUQe1NbXHThTippxgaMfbeqBo6NXeIxPvqwTfubA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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