SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c78ebee60186a2a94ce708b75d610a978848c12d3107427865b5fac084ead02e' 
  AND token = '1rLaQvieynrxMH1zLD4dkU7j9J6oowcnAYqxS9TUTLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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