SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d322ff238ccf71206fcaa70f5c263b196b92d01552199f94904da793f6c5f1d' 
  AND token = 'SMz/eC20ycTW8ljhXD64zm8rORgGmSNTdOGtKB8cLYA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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