SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd47134e5d970027f39f452d33c614d9b61f51b2b940633ffa715eb90138757a4' 
  AND token = 'LMw64oz1hMAT7HRaNIuH0hy9nZB3PwWjtKGu1Gwnluk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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