SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ab26b0db4df8342cdcd31359097686a4bd4189f84c901d62e1896afba11a44a' 
  AND token = 'o+2ZYu5VUy7L6ICLifUkJdFVoydW9HYGqRvO9ZMgWjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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