SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6394d4462f4f36bd41f1fc249d034228c69ce1659623eaa2ba8bf26264551c2e' 
  AND token = 'rzZXEEvqLSMtyvrmL00+bkWoJHbZSrawFTvjvlH4lak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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