SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '122e06c2a8b36357fdab1f23fd0adb1fa4fe055a2fb6341193972ebfe9c4ba5d' 
  AND token = 'MDZsfUH4SfK11kFmot/sA3LTRVl75M7ZA8lK7Mcr3zI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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