SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '95e7a35cb218dc0dff899aa35f7e4997e0f989be02b479e095861153237aa370' 
  AND token = 'a84MNXEgrUsEWZ33mzTcJrcIjDDuxZuBRI9Yqn/x6Hs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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