SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff973df2f68e84c59863d59dc96c7825c4ae5a3b199e4744e7251a7826c57ba6' 
  AND token = 'L1cDRVWDSuEliFOCLu/ZkKKxQxHnvomhiqXRH16fAvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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