SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a5792dcebffbec229c61a69d075ac8ea7bcbe16d2127c0fb50ea48d3c4676f3' 
  AND token = 'lb4d+NTTgwbwXKvkBlrYoyINI23KbT7ZFVS2QfAHydI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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