SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6c25f19aea648331676c7fdcd8f64a585d19730abfa9513c71adff222d29f1f' 
  AND token = 'rwbzlpRsgF87ZN8/VgjJ3hNG/ikfL0n6knH/1PFnlpo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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