SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06291e734a02499ea7038b27357464e40feaaedb320726de89bc449d8a33f56f' 
  AND token = 'pbWxGp11fj94TkCm/XwGzE5w2oKbLBZkp1H/FBuh7GA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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