SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef9228f07a36ef9cca07a55b3699a14852c8d54da38454f2f35b7ace089fa823' 
  AND token = 'sQK9dQHzJwoz9wX4HrPVD5Pk3VtwjdUhDCkKRJAJ+7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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