SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb7561be03182218a16e4025f316a8a283c60a621cc258a67cf06ca451beda72' 
  AND token = '0Lk+zwUoHKY6awHRe56sqgM/Ql0G+7QlMku4XOZ6VoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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