SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5301f8c0d1a04459d0f96cb5d02c5feb36b6bd2c6e1f7dbe593affa16e68ee02' 
  AND token = 'BZXHVXOeSW09XggLJHh3+ReEd4AlCgrd/b9lnIyuoZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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