SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44d21d11378bfd998bccc5ac8e3444aac3254f71f4517b40aab8b535486afb37' 
  AND token = 'jEzv3AlYbhOvfaZIJBLuW/Qs70Ut2T8woiNc2932w/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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