SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7589705538b18e2d98ac348cff2f940ba28707a2ef013f8566d30c0028cd8354' 
  AND token = 'UFAlqjiyz70BHKTwhny+TgmIJrod5uSCQ25qiRPj0VM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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