SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33454d503259046c0bc57993bbb9b592ab0d4b2f431d16f0a3c463afc1412e5f' 
  AND token = 'qHGA7pD/oOB+JDYhTi/Bm4TIVxlzZEzQsEkvj3fumB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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