SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa71f108e66b9d17050b3b6b3cc7ea59a4371569de8de1d19734f78b9b2635a4' 
  AND token = 'QjdwwtW0oc+/Hh7YiYDRGpFvVJZhylfOtRbMvGQCSKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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