SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52a134abd8c9be85be302a50a18f978aac4f0707f6486ddf7da1fdf499efff7e' 
  AND token = 'EWqGCAbjd1bDQtczgj5IAdxW9if2WKB9wUg1p7/2vB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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