SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be92d8a20666d5efcdb5887a4a680c852d6e441e1ac12ab6d4648548368f8f06' 
  AND token = '3Txo0/jmMjea0X1PgyYDb9Yw84BwAQ4tuagAIIhFhDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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