SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd706a2c772d3875a1cb716ea55538955d5c3fbe3f0fdea10a7f596b2d2573808' 
  AND token = '/fgRZ9mumqtrGrAqLW+ggth+YlEJOS1QXVpHmWqvDIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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