SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dc1856f60a6940c7530c21fba7fbe88e651f5c22ccfbedf91e8c3302cc3e627' 
  AND token = 'rxHqWCl7AVu2KQGZjP5UVPL2icbxb2XmYlbDbIuvgFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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