SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e209832fa80de968750399611edd5e947ede7df5fb4fd55cc96b1436fa37e05f' 
  AND token = 'kld6KQjjTYdKox2DHgm943h6OaiGo54NGegtNMpsdOY=' 
  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"
    }
  }
}