SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ead42b943a99ec10919d8c52b819ffd11ae57600fc505cc8a632a843df90c61f' 
  AND token = 'oZi5Ve9kTYTC6iy8roUrCkmgr+oZQa757lhgFpycSjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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