SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bca914cda7528779b6930b9e95f58b2c1366b7410717e3d765a4fd014fa345f' 
  AND token = 'DX1gvubkF93bTxIw35dbFWdLAFyVb6JpAvt5EW2zGZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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