SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87ec8cf84ebec211b91d94498a3f45ffc971dd1a864dbd3d9743157ad1ef850b' 
  AND token = 'dwwP4wpGxsp+qyue90NZaeVMVpyHro0tLXwO0oQgWt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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