SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'fcbe699c36168fb117c6d8d753da1e4ecbbe92592a57bda279e0fcdbe903f746' 
  AND token = '8A1X9AdmVcb4V/CQDy5YHgRySIJXxX7iMuTivRuGMAw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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