SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '951af94220ed3c8c804b8dbb950345c249a78f28807d1094b257c51e41dfa759' 
  AND token = 'PrX+GVH/7HLtYYTQTh96YOQwvDyd+BRaqqQK6ABhYlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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