SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc64bdd1a33eb396f1f8cf147bc92345a475e7f4aaaf9407182add325180c179' 
  AND token = 'nUKcc8PV2rqtyVZbYXrXfZe+pmTQjLXBLnB+mRFa0ss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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