SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c8e0c7c3ed0a8db6a654c50f48538061a509ddc02acffd69751c0c19fbe77b27' 
  AND token = 'BpJHS7okPfUywqNJ4JJBL4HIR8NAwv8TqGwnUoQ2BGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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