SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5efe8c2b79e30f0036720aae5df0cb59434834e6210df10fc0ecb82677e2fc72' 
  AND token = '48D5PxGYdgYnoqC+IdiyPG8qJkTYx2XKc3ehiwZOCac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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