SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ec8754f37d454602871234e4ff373662adc9ba8eb71eab1e347728da9ca1c1c6' 
  AND token = 'HiG/yt7gZhqQqr7CkAUSpKim1JvIgj9MYrkjn4z3uUs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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