SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cb682c3179ac41af8e8bd22f037eeae1159b3276fb88a05ba2316d4e78c2536' 
  AND token = 'm468znOML7dwhYTiiQDF/2MfxkNU6IxdjRPpHsT0/Uc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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