SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c2fecf828d98a5bde91945225aa21db58ec564daee4169e14674d2e41cb8bf0' 
  AND token = 'OZdu5BA2Kv5v5gbYLrbJzYSoyqXLJriqZzi3gbj48TU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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