SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd746ca22d75d0df54a076821476ec1f3323a9b5fea5a73836f4beec985a8ef6' 
  AND token = '53+qMzzs53WmxfIn9io3M/gHJpEO7HDXpfRV6WKNWFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}