SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfb9f8e9c0e53834bceaada18d844aa8f89863dda0e08826d334c5f48d7eccd8' 
  AND token = 'KLtlXLiCg8n83NvfwMENdHXIMM+FKgxIH5Fos8YFuWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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