SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e7568e4d237e48695ed8586af7ba61814ebec55afd9144e508e9f90194f915d' 
  AND token = '6WpHmejexfVpcQtIf4K8E6jMBSKKzvyih8JOHFYujpY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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