SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '919ca5f75fc40d99cb6d6275bd2871f2251bdd08ab33f7249b86d4e0446f0669' 
  AND token = 'AD6NzJY8oJcuZ02Fl1XPVw14AllF9zM6yw9qFWdk//M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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