SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '246d07429fd4a438a9fa11475e340c5a7d712e1528bf4d579951a4540c85460e' 
  AND token = 'hjaihzamGGNzwrP3j3WFXGAo1S3c0JbSn5TUw+cQOxU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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