SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a50d6d7ae31433fa714f298bd686fc1a5b0c7761f98ee9243a089b603274c2df' 
  AND token = 'EWa0/psxfq/B+mlyW++zILXNyKVfZ2L2E9X/HpouryU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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