SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '298ebe30dfa66864ad5e2e43b46ead9384e7dc4267ed6f78d7799d5071487436' 
  AND token = 'oZXdSWpbuamW6ly2Qox7UZIJRJgv+tflZub1T3EFRzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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