SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad74c16c858ceb484f0bb918fefa5407b985fae61bbf0a4900f432fd5d0f4a0b' 
  AND token = 'qd7Z6bIatvgJuMTBO5sB0AfwvSlQB/LlVKZqWIRZo5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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