SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '813f590f95fae2b1f73d8efe4a8513fd7ae7283fe860c349002f669e3faa9161' 
  AND token = 'yLtDrM7fAUH+QB8eVXN2BXH5zsnj5kY2PqRzhXQ6IfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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