SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf306f173a9e9e064940e4c65c007f3a37300299b5c035517ffe96b91f365ac8' 
  AND token = 'rctxEsNxBjAHnZAcdsSXevMeF/ImIHCdswEw0Zabp7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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