SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4602b715207374f42b28d13b365660c212ae943463ff99543a3144ea72b8660c' 
  AND token = 'z2gLm5UU2vZyRaNqkoojlxVBwPIkmpjA3tvWKpvHu0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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