SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20423dd613a5c02df3446a816eabb122528d24341fe98765b23f75a24f8b97a5' 
  AND token = 'XyiFYTRvbFmmcnLDQmNlelrySaTaPbHMXXqbom7iNag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}