SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dc150e190ad6ca8bd5994e608e273c4bfdeda1215cb686ce8d17b2470aadf98' 
  AND token = '35UYOyZoF9BsLMf/E4wC2q/j+JQtfTnrP7a9sGOwTBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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