SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '09fc872b9d125bb2dd686c85ad1578971522415bdd7ab6d5a68098be213789ff' 
  AND token = 'KS6i/gefeINvJk2oW3QHpKXpJr2UZWXkk+LwB/E8NCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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