SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b9c06ab080e87d08fdafebafa56d58e3f66e05b84aca46e4286965384d7f0606' 
  AND token = 'jDzdHpu1ydL50EBqdHhYdbD46aVsVrb0bydOi8vFFMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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