SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6338f2c1bab9f1d68103686b4bd4a740fd092a6764a324652099800380938cd' 
  AND token = 'XHnsHAgKvyCs/ueziJUxTZhG+d5RCBMcpwXwd1EcC6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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