SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '21ba59cd853861a30e9cc1a0f4885d2d52002a97ce90848d31b24920c35c7b8d' 
  AND token = '79C8Y3DPwEfBXQ9hjC6iO/jtLvaTTuojTUp7GSZn/uY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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