SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3f12bb8a8f0559cf760498479410f32d1ba94c8779bbca1cd0505c16ff29de0' 
  AND token = 'RCJ4FDzHI/4LX/UAKTQUFljV65UvnF1sTnOEjY/jF0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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