SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8682a6f629865bf11d916b4294e4e5f0a7f3157db40ed9201f9c9300c9e2af67' 
  AND token = 'Jypa2YiOuR+aHjIGkQ2gfvWBOh1qb68pNwlbAWiFksU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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