SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '691ae25ad05fcb55580b30dd3dac568569215f04efba56da2bd757507320c933' 
  AND token = 'oIiKfkMcIUx7RmxKgXSvPRW/bspXoXLSPsmIKBrO74c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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