SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46584bb3f81ec44793be6371270d264ccd9ff7ea7d66914df3b53540dbdaaf2a' 
  AND token = 'Enil8TrmY6I+szvB2TGk8iC6qXsZHGjoT+3MZNWfuBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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