SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '026c7874da5c574a377a43c99cba675b832a14f74518c311a0f8df0f516bee10' 
  AND token = 'fBOsd+ia6VcsPqMNMgrpH7fmcnK/eJ2Q8N8PdhZ+jCE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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