SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d6f1b262fdf9e885839ab679598d1532823376b5d9e4a1fc138401f586ebc8b' 
  AND token = 'xKYayLIqnyiwHzS/1E/G0HEJy2QOFzvzC4tVYcntCtg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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