SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2842e4f98ba9ccd14ade294fde1d13c239ab3d6c3154f578648ed58661566b00' 
  AND token = 'RPvw5TfXBSLEaJnWB/iax3wNrYlLJxpvCWAb3qFCm9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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