SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd14747e5f36cd14451ec0805d9c761e2fb9f423f4471f8fa73d84a983026d689' 
  AND token = 'nPqnNiKAqVLfzf2uHGGygh1iw6Fos2CNFTZx5KsIe2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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