SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37083cf4be63e376945fd8b77e2773df6c4961c0144cc889761b9a176a402cbb' 
  AND token = '88WopsZVXJIOKiP6o+WmFuYaWWFHf/4nzQBIVwg69is=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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