SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '046c43c3ae13f7bd12b8734524e1d025a5ff72f8266a6f0c1bbf208596134a4c' 
  AND token = 'eaMghIRyNMnWAspKLzwKVn93s7LlWrRW/fiVqHwTFCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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