SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24324d1486691290e0eaf92b11b81d43f15632d57da61c14d3447f47ca53d13a' 
  AND token = 'ZIaUK9erAtAXjGCzY+wzj/7y8MbXMFUSmPjgQE6uI6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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