SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ec7832a5cbdab75342f68de3fdadae019b91a9079b59cafb8fd3b08f5e08fc8' 
  AND token = 'JUiBrRuodvBAizz/g5Hg4CXLyznVSz9WGk3BQmKku70=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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