SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93adbbef4a7a4fc104d92c97cc1c0420d01936b54fb3f5e10aabd4f943626f44' 
  AND token = 'Am6hus5RBp249EGlTqG/5rYgnJfpWectQiXbqYiR5Wk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}