SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fbaa026856b879eac15024daea02463810852da37b12a9ddf97e2fe861c224e' 
  AND token = 'sOq+boQiCGMxT40hM0PqjwttTDMLU0eOPN3apMQ09eI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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