SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6e54870216786933b391ce18a58467b3586373a61ae32255f490894b3d5475a' 
  AND token = 'ccR5VtOcoMh/vxDvp0+2t8yKRJEaOKiyQ0a8lq8YreQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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