SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ad1c5b75b692d20aec30ee53ed22dd396f9a37f71918d4bb820d8f248847a7bd' 
  AND token = 'hGzZp16ydXjFgltDbaGTlzRGw6OWjwHuVg+bRpV2VFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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