SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc710b51427781dd24e5dfe33810a0cf80075e33a3a2c66bd521c028b86839ef' 
  AND token = 'ovb2JOVVny6HD9MZS4K88zt/uSbyxFZf85broKsRPFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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