SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0523827c208af206a5505f0470aeb32240e9cc4c96db64909463d0cfaa251788' 
  AND token = 'p2XLoGiIREuy0HMpflZWcxXlOEGOQf4qBXHA8ZxdAeM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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