SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4eebb7ef19c79f1f2a0d95977b5e99c227f8262c6d9457ff75e9f551f52e9ed4' 
  AND token = '//JX+cK8VOpKChGl5z0IG/4NhRyojM3vDqNfrQ9DaUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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