SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33cb85b209bda454d77775b3c4f37a01292601cce73f4922886230e35f9ddda4' 
  AND token = 'FJnwTmhFBTBvid0UP2rVDTpj8t39qntBKbBNOg1AtRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00066

JSON explain

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