SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70c100fe5ae533c33950625bcffe02ae2f1172a28e5ced49b95809cac701f17d' 
  AND token = 'MVjudQ2uCZh3gJMk8uB5DseSJTPr7ALq2IEotOz43as=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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