SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ba81b0328dae2fb6b067dfd7286e2964250f03c18820586b7c54333872f2134' 
  AND token = 'GA5sBgtszH/VKqpRlZjvrLt3pe0QdoksQzbwAzYVodU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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