SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3ecc28febb55c42561aab76975031aac3becc0c6bb5bafe6a068da18f1a45d50' 
  AND token = 'FrgLTUXW/ilIMiExuPknniC6JiIMPpdhmVAaMEofwok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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