SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03a8c1e1e95f9818a545d8331be4ac9ce387074116719a313fb64d60792ac83f' 
  AND token = 'bLcXwaP8k725swL68lpNfFRjHF929cWa5ZHmFEuYo5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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