SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb29be802400c41e330a9dda025b4abd1bf1c67009bf26a3ac96e915f959afe2' 
  AND token = 'vZvrEsPTsOUHRsK9qNlRnOq4LGyu+i9VhAkeuHZbS0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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