SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '23b694d4fc6c3311c7377401cc50fc2dcea86eea4b609608b4b125bb53c56cb4' 
  AND token = 'C+VcIrwtkzG4GFQcqd4BpIXGlf9RvVrtXJvjRAtVZ6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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