SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16e01dc369ced62ecf02c82fb49a9e0fbd91386da2192c319b650d0249053242' 
  AND token = '9UbZ1qo1OUHccjr5AEpwbItamnpWgWp9zMZVCWfUxw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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