SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a40fd3557fb74a2bc689088f136712c62ad0963488957bb16f59fc72cf954806' 
  AND token = 'CQi84COFrQt71NnrSYetFWxthfNiSYE4iBqno33RCPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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