SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46f8a2b935eb442c3f9002611e350fed18486e74e6ea0de1a331c6dc50fb2b6e' 
  AND token = 'WQhbawWFyDMtb268es8jTmZA3FnvTEMYXtxUkDTN6/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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