SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91fbad1cdded16e943c91be4e98cc71bdebf3cbbfdce53c485ab0d56e55831ad' 
  AND token = 'oEf+eOFy+IXDsLI8wvEPpCyCcWIHcxe2dRFqq6kB7vQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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