SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be3a5d7f67e2bbd16e44f257e01fa4582e561b216dbc774f2374ee63f79fafa6' 
  AND token = 'OJxIWui5mMHb7PuIflxnNUIDvUGShPWQWlauDCW23BU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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