SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cdfd605466695736568cc89470e1b8b6cea81efe0d48f60476de03d12ad4f27' 
  AND token = '9WwEqBmRsxohxchDFtCiUKwa4bqaH/7r6jVyoCkz4sM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}