SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '780b439088202c9a691c843af5b26011588b8c054a8208f2f63d94452c2afc14' 
  AND token = 'yqWXknUsdBq7XJpwoRYiGukeBv6ii675XwtSpgL9N6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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