SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a015103da2cdcfa641e4653a30c749df8bb4f5b42e639529cc0a9c809b8c8db' 
  AND token = 't0D6UgByHSalCcK7ErmE9uLXkeMbcIU2zwHItgH2AuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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