SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '512955443385ed69f99ff074d0d4a7a7b56814965107bd200a809ec7ce46e74a' 
  AND token = 'ZEZaIU8+SOj2VWZC6sq6d9v3yggddt6bvwk9yTZKB0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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