SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '437b3241348ce8b1bfdd6d15445632bfe059ae36a9d7f90247d2640adab65704' 
  AND token = 'GUQ+9TLKrYqEAWhZUvhqIg8RuMjfGuFZzieQmR9wIqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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