SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '674ef2b0c190b26065598f5ddefecb1b7d700f107e5b65c5e52f63a9a3b880e8' 
  AND token = '8kD1OWwwZ/2hDXPQWcbGBczdPMjwXhZCaAXdCHsKXtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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