SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24f7b4a99f35dfa84abadf6a5178e9c5af8e490144120bdf6be6fd4231c1ff34' 
  AND token = 't8zaIVg7mOyHOY1Kf9lVp4fXYOcnZ6GZKjvZQxLCjLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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