SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9334ebf32311ebbde72c8c73cbb68791eb25055f53be847fd332562ff32f4927' 
  AND token = 'eWDR8aBuCNEBxMbh4JaWa70Z4fNJpXlkB8hacqSomNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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