SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c32594f03ad71efcd493ef656ac18ce31883c96c5df258aeb7a84b5fb71e307' 
  AND token = 'VKGR0nWyzHBbWwATOC4egsF4h11gZMl/NsQ/XYpaSY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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