SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '46cb77dd9b2589774e3392c17b98f69fe0f15f182f63d645474f99cc46430488' 
  AND token = 'B5srmdgvquxfDCK2rXCX3frffWBZnmFf+QkxPPd1xQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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