SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '219cdd4a56e263fe82c2216297752b40ffdbe17e7ed36edce2e16a37ed52898f' 
  AND token = '7K8sBQqESEkxnJLHBh7sjUh+ZjnMmA4DjkCobYrDOBQ=' 
  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"
    }
  }
}