SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5f4525ba0cdcf2e01ae7abf8ac64fa3dbbacce0f8c832844fb19b250c6c6f38' 
  AND token = 'PZ3WLmo5xWMPCJivBCruct9ycsOoznorucSurMLoPss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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