SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fe80974dcf96d02bec423b53c500390e855010d95ac609ddc82aadd3c137f3f2' 
  AND token = 'sFQWqxdUbJ6K+23JQIlqq2KdWov0hwJLerq7YVXzdVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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