SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f508a7ea0cc4de48e6b9c604511d0cf6637446efcc6f408b1031b6be6ff3277f' 
  AND token = 'LKFtszW85K1zETWlLBYjQOZsjTlK3v1pZdGLYaB+/7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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