SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcc4ef4c09143ee455b26a555a73d365102001e4fb90e2cdfa6105a88a683ee2' 
  AND token = 'FuaGifkjhJ3Hxdp0vOkF4srMGotrCSvGNl1Zl3jG+lE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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