SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20eb4f4347d117ec2c466aaaf1ff2b9e8ea10c8da7ec41ffe443534f2fec6e82' 
  AND token = 'KrWPXqmLD0wJZKbWyLWaIVfK3ct6Xb4gzG9ZN/Y8TNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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