SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acf5810327a5d909291d716f82572a249d30111d124b5ee38eb504c4d9f6fb95' 
  AND token = 'atE1ncGWT/Ne7j1hfdcGZKQkNwwyfHM261JQ7mIvJUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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