SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31232fd12a2eb5758d43de75a50eac089f285fd48c7eb7b8c3d151ebbe494f03' 
  AND token = 'g7EiQuI2Ju/Y/9pvDJWOhHFUZaZditSW5pzSoN6jflU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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