SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '576115894d6797eff52bc9ddd9f24d7cbbdcd19b6c8026005d00eb2b09270351' 
  AND token = 'zq4yMKlnrdVshP0rq0VGaFyDMWMvVdNsatsj9NvY+yk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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