SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '678d7f3093bbf5c6adf422df0d97f4ebf51acf4a19ce288302da74b8d8f9c7d3' 
  AND token = 'rrVKHgYu1D1NQmhELgeuA9g/vv3aMUKEzLGRgzgjbck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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