SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0791aa46c2524897bbeaead0015ed58d45378566a7f1067336999a6255c75f10' 
  AND token = 'G6Rwn6z4JMBWyphEw8IkJDKuOg1xE43X1NrJLOXUbGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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