SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '750c28e48e1bf87550d57c82cc5858045754c6c953eb88e87f1cf5e1df16b559' 
  AND token = 'PLU0QI1RuCc5g3kwETzlSayK3PlhmJKUcc5zGImq+vc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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