SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b66f51f239c811ebfe0ea48b4b5957dd034fbe92852524afc2b329488e4293e4' 
  AND token = 'hlbJnnEVXC4bL/D1FL6z+NzRnk3UitbCX9LoBUyKvh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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