SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e78f0bf7b8fb42a0cfd15f1cdc505abf10408a7590c26e0065bd7516b960f10' 
  AND token = '2AL9mk+yKt/hpYQkIA75euZvQeuMYTaIDX0MVnC2vfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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