SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9f08571ae90d6f72e3fff2bbf6a85c221e4701f70839cf4835946e5aaf9d6f3' 
  AND token = 'nle2OCKr9a0ISn8FQY3uIQw1z0mAch4IyH5VTBY2YWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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