SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd7c3749372aff9bfc21e4e01532849cc449fc20472f1a194208c1fbef5f5fb1' 
  AND token = 'AyBeEaks0mZ7Z1z2bQ7JZ76j206VqHuV0sObW/wBIeM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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