SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6652b16024c69eb0050ef88a66a0ceb6d28a38fa5a36828cff0f1b9746b1fe75' 
  AND token = 'fg4kFhXvSiRYPeCQKqUVm3fG++MjUEoTCILH0qgoHfY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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