SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2711c51a54b35cd907bb1b8df2a9f94b5eaa878e1890df0ce940067f62f2a89c' 
  AND token = 'VmoK76gnszxMaL48jsBfFDYhofhLZ1MdxuCVsyLNJ8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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