SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '683f3e9277263df81750ae9e5cf35497a46b8571abdc1f7172955edf6c91fc3b' 
  AND token = 'VhoMpueNSwXaPLLWcVO3/7lMgahJGxvFgh50+6md5uU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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