SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb93d108429b657e72ff02a16f558d318b6147b68633373ffd2942e8e17946e5' 
  AND token = 'HQ/fWlVAw1FL+Q9cDwtAshGyJ0mq5rPm+EJTIF8StFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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