SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37fa84efb6fdd8fc15d02b8b26ae8b6316906ceb97313d202e1b4dfdce2d5321' 
  AND token = 'gfDiuRhaDDZslhGiLyS5m4gdFYLwsOrxOyKBlvJNhNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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