SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b45a732f6e0c6818f91ee19c298fd06b7f6ced00ef4ac9e71072b54849fde222' 
  AND token = 'OwGbrJqFkWap3t4m4VLM+o/Jq850dForHQfKjQ+kSvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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