SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae81371fdcd27a423fc15a189879f306b2f4e9b20a3895f5125d3d9bb3334d7b' 
  AND token = 'wip2B4b+LLJbicV855xJfungGSRFBPdWhJTw+PV6e0Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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