SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '03a6d0d34653acaac972673ff71b766b404e14be302961064bd9289b373ed810' 
  AND token = '5xALTW1gIOvq4KNhYQFNR3LXaWqYasjr+dJhT6uQWC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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