SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e9c97d9571c1091372aaa68215f1c22f01768019fa9fa22efd1aefefde17f8a' 
  AND token = '5TyrNCv48tg6pvli+V04CCEOIaOgIlwDf0md4m/lpx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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