SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ac777fe07fe913f6dd68906ae7e6dbe2006a00942afe4e3a24b5fdb87102b40' 
  AND token = '0PtPk0ekyITQPkMAKqFdES2uto2eAHK7T13tQc9VjaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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