SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2d97bccef810bef8c34b599a380cd45cc418d6884432da8719f2f1120aa730f' 
  AND token = 'In7gygRlk/cQoyBPO7eYmj97NZfeDTezYwLvFLxVgSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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