SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b71066b08d471a3b7302760bdcd798d6af1c6545c4fa596947a5704e1fedb592' 
  AND token = 'zfwR8vhJzYgKVCmbAEX9W97OX7G6VjS3FODPg2rFxOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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