SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b140b5d1dd25b3df85db685e25712c10b9a89246cd0dea0205a49b6ea7da4f0' 
  AND token = '8Y1MWFmV3ZOQdFFmFOKPrEDi89xfTPcrcO/XfuLZkTo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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