SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '374f60e87a693e06d8dca44623ddb7854bb66d1b05c408d1380f0d98c0c8a29f' 
  AND token = 'jyM5RWjC9inqRpU7YeVwXW3q1elJdHzYzwQ4houvaG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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