SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '120c518e4569c3de9c2e3fe2452bcb418253002a926b721ab4ca817a6d1f269e' 
  AND token = 'rvt4iicLW27k11KY7Y2SWq1HaxFbsY8Q2gmQhZTkbUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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