SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '173c3820feaa25f227e43139f69d9e43cebd07f6a21bdc8dbddb5dd2a949726c' 
  AND token = 'wII9QoU5XS8Z9JPUXXKutqNO6JCBPUZNFBtwshTdixg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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