SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4604ee47126c7f38dde01000702326b21b4c68ce576984300402c5b5992cab3' 
  AND token = '2FsekLcNYLPURIZxvvjArF5KSDBi1i3G1I+qPRa8R30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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