SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6929d80e2118d0208745a57b3f6d3bf46208843984074191f4dbe5868ad2813a' 
  AND token = 'asc//2nKBfOe4HhjjKaevMKVz0iGAtwT+QMXZwf2ty8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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