SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f47bc93bdefc3a8809b55fb8f9121764f7653d044c92d8d6e2a375203501b78f' 
  AND token = 'gG1kbHl4BG26KmCZu4BvW/STP1hZxlNa0hyTJq3fREw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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