SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48d0ed50ea7ead74d5b45865c1b0daac9eb116109e5ba04f03b9847a75c275c3' 
  AND token = 'Nr4xLnmSRdpNsLxbtrfkg47HIbrgTUJsW4ZbC8YgApM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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