SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4256d6fb95a3475e54889945f6c72267590bdbeb014fe2e27c9f52d6933b2000' 
  AND token = 'VNI3ID1k5zUWskJXYU4x3n1CKg4FKh4gd+vw9LS4GwY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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