SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a44c73f925b4bb0391b5b654b685131f97d953e6ad8b2d2d29aa87678cf3151' 
  AND token = 'FMMadK7jqarn/KWN5zSIg9nl+cXw/YLYup9z9fpkAZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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