SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70ec0f88d798b5836c2f7fc20d59a304f4bc899050c28cbdc58b0e96b9b4aec8' 
  AND token = 'g+zIJivdWjZ4Z5mvDfl8OtqBQ1rAxrz/Hwxj/elgvAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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