SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1bd49e8cf016757e97f85bd0b3524a64d98b7bb75e6ba231ca8304c84fc41274' 
  AND token = 'FuvXuAfr/DVSgEzxSnPWQaKjvovlk+ujJ8GGTwpdWms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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