SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '263b4d809dfc970ff65e220d236624962ef529d6ae141151820a8b6ee673e096' 
  AND token = '+n/b8NjwV2J5wCOrIoQLRCpon7gAfNUCnioNyoTf6Lw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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