SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0187935d2384e31dbf94c41c83cf0753b8557da34a647acf64eab428160d44b4' 
  AND token = 'Kon1WTPQqPTqqboWVu8CbXLKpDcpB+WAfGpatVFuy04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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