SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'af3b076ef9a6330fcde91ec668bb880735d9aa2d7e430ade054a8c3f26304825' 
  AND token = 'KKDeKVPuK/aROS14WfTx3UUKZrgQD+BfNJhmMYjwgdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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