SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83f150741dad60cd5dbfae4c3113b79ce9827c446c50a625e25742fc2e0cce38' 
  AND token = 'yyasz/XdVhW/u3RVxNDEzR2PJRDkFhqbeOCmh1H/em4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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