SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad02275682861fb0d973ced060023e2c93a33291e59cf127d5e12dff6eb8e7ed' 
  AND token = '2+I7ZyS/BzLcWJBCkxJYbFsWo14mAstrhDtbQiHQyKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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