SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c76d1f1c0855f5034b8fbad25a02fd8f5e3ca67591a55db94b64299b7085a108' 
  AND token = 'Lcv0bqS8iDM9Nl6P6Bfrf+7N6gJETA3hv9c94BPwbuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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