SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abe4f2f1b60e6a03e047709aa24085b5508a97891a0628d94b25ebac56e1b5fb' 
  AND token = 'qRbS31OeWvBKLIuRe+E0afCyvxk9a8zfzXsYnAgbjF8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00066

JSON explain

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