SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02dc2ec513c9d526ee7c4c186cabd94ac93dc1ef8832b010a8df1c641fed4768' 
  AND token = 'xXXwa1P0PMHFZ9fPcLTL827wMJC0uBXQyZLlnWyxXFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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