SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '88f134fbe4253b1757d5aabbc76f3031f1704808cb5c69173c0c31d99ff92cea' 
  AND token = 'a/BRPRgGLK+S8tgmRJnMf/tP5GwkJjwySB5uf8FDE+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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