SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96c08f9d08f6e6ec0bb51c8a73dbe9c638529d2656e0da660e5b4be743ec2509' 
  AND token = 'rq8ane90fUj1N6d0W2c39cGK3itOgBP4v2YOWHPrQIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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