SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6c5ba2e9c72634b28694f7801932375fa26a7bfdf1104f7b6aca44aeb9b4b9b' 
  AND token = 'u/fwWYWgWgneLJrpEXKHKnbnle8Yq/i6/u+J38lwA5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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