SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '66d1582e3dce794b4aff8540ec92e3b8d568f4212caa7b1d5698b263c952fdf2' 
  AND token = 'oUeBdzi4u5XFx87Q3I7J38lWTh+WijInOKBwSckqYYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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