SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be277b87e1acf04fb610ac5f7eab733d9b44513e5e4663bec4409739b2e69b77' 
  AND token = 'Uar4mSJ7oKis3NRU6wVXmkPJIZeuKkTUcAyvkAisy/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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