SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61b1c0c85b6c39c6d3bba8b62bbe41ecd3d78ecd77e6a86c8422985d4952c0c1' 
  AND token = 'NpRQtOxDVWFvQ1g2kUzJ9/1AxrnIkXd7OY8JBmanzW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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