SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2a377c434ed0e35993a4cee1fdbb79016dd259d3ab851cbccf61fe6418d950c' 
  AND token = 'gO/AgBO9q5XZHQwulE4MGAAimygxAAJnzAUa85Pc0+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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