SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4681449fcf2718a3ebd36927035b1633e41b8e8013bdc6f80c0dd22db5dec5a9' 
  AND token = 'OsSBEGQVBX70GDc9vw2YjPtmmW7/xLIsMzXiwgwtr2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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