SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '156c0b6c96ca81ade2bf6259cd8037382758809815b75911112c4ad517fcdd30' 
  AND token = 'NI6+ma3u6XdTEU7SOetNrusSPJlJPEpE8I9UTGtLnd4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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