SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c616503fbcbb7cab780bdab16503c680229a4e353249b5cf38f516d59a9e810' 
  AND token = 'MJHhxr3zewIIrdnPA9g4ZLqqO4g7lWkJQFHtB+KhxEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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