SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d8aca257206f42a99cb4b031ebca5318ec94958a5a062a5b36920337d6d43c0' 
  AND token = '0GYo4iPpM7X+7ZZ6a4DM0+rnBhYaH+7Rx9WvKLVKvYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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