SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e66098492adb12ce6656bbbeba56770ef7b847c80a149344405532b4f66652f' 
  AND token = 'c7JVKiy+3qB/BMbitqqXs3APGmOH8YmyDdJOgKpLTeY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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