SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e5ddbd3de2cf4b918c155d370a3136ad0e28156803fd5e82fcf28dda42d5bff' 
  AND token = 'gk6jblzJm0BzxS5xYSZM7K19v74nCDEy5CK1B9GPNs4=' 
  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"
    }
  }
}