SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fc9ed6e0eb3f62ec7798841e0a9aa6b0bca22543bcd2883210de13c3471f01f' 
  AND token = 'ByAX+5V0G/+euNUXYwrLA2HIzNLjRsid+lmb+VhJP20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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