SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9799d3c1f245b868dba2e8447a15c98c845b9c352446173e722f3a7058a4b593' 
  AND token = 'EsW8xj4eH5Dy+zn+qee3qRYIDYiXMPsrt8neJQF3SKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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