SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '376db2fbabbd4f03218b89d12c2081b63c85296a58e6e58686a2154ba55839af' 
  AND token = '+FqyasCp09JkaB4OZd+vWnsJJqchAkebTDZlwc0TFlo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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