SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0e39d0709af0f1cc539988a6d373ae43dd653db5e2cebb4adf8676fff1a9621' 
  AND token = 'Jiv04Ah5GSuG2K2OwmvGNQqbJ8s398DlY+mxnifzuIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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