SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c189c2a5bdbb33b71b4fc270c0c58b401ab368c00173f4ce055fb5f13da75946' 
  AND token = 'mmwGh3liKa5nUNmRkOaYYdeeHxTYZg5yNGAP5UdQXZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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