SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c37903fb9763ace14caf04b27f1465aa93308ebe0e291c47946dfd11da90db57' 
  AND token = 'voYHbIuBotFGRIsvnxZcToVxvIo7sgt5un4/pK01yMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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