SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c12259fb9a3785aa7f963c02bbc20797b646ebe57682c8f9640e003f79c91fa7' 
  AND token = 'WBMW4wzeCouleUKbVFt6+x4O1SQY4qLu1KeC7w8A12c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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