SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62ce17d2e63857875814e6d258cd61c874a919431cfac25f1f3464d779f66083' 
  AND token = 'oyVPk+PuZ+ENqh9mYuUUspydyHvdWhZeiG/sVU8X994=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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