SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a492827e6c2b711e19051a3c6aaf9a53486f6762d4301d373ae16008b4daca73' 
  AND token = '9cIbLw8lfrIHnJPqqFGVB/uXrkBvMmCQriWoK66VxbA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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