SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '39f4b4d8f737e9686613d615c3ab081dd390bdef34635c6b53fcf732174bc490' 
  AND token = 'lMcfh7JcRyaVqCblG/7DAaY/foWAx4o/tnTwvAMh+SA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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