SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c856884ec8a477c4dd9742590e46eef1f998a716cd4e927fc3578529b040a16' 
  AND token = '8A6q09mPfoltZ+rzsKxyZ3wzzYBEkWRtTcn7K2awWsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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