SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6deca24e2f92138cdfc06c73d222f373746a36546d0b24d59d24037c9c7e2b5f' 
  AND token = 'baWWKbffXdn4BOE2k9mWt6+UGej511emryzK5UgPfvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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