SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9061819b18b6288bbbdd62aba7751a4f539a365f1822a407f30cf5524ef103d' 
  AND token = '3MKahhMiVA3yX3z/WAKZtSkz7nKjYGqKzZlPsNwik1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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